JOURNAL
OF MOLECULAR
SPECTROSCOPY
13,
17%
183
(
199 1)
Measurements of Lorentz-Broadening Coefficients and PressureInduced Line Shift Coefficients in the v2 Band of D2160
CURTIS P. RINSLANDAND MARY ANN H. SMITH
Atmospheric
Sciences Division, NASA Langley Research
Center, Hampton,
Virginia 23665-5225
AND
V. MALATHY DEW AND D. CHRIS BENNER
Department
qf Physics, College of William and Mary, Williamsburg,
Virginia 23185
Room temperature Lorentz-broadening coefficients and pressure-induced line shift coefficients
in air, nitrogen, and oxygen have been determined for 126 transitions in the “2 band of Dz”O
from laboratory spectra recorded at 0.0053-cm-’ resolution with a Fourier transform spectrometer.
Samples of D20 + HDO + Hz0 at low pressure (G I Torr) and lean mixtures of D20 + HDO
+ HZ0 broadened by nitrogen, oxygen, and air were used in the experiments. Transitions up to
.I” = 12 were measured using a nonlinear least-squares fitting procedure assuming a Voigt line
profile. The broadening coefficients obtained for the three buffer gases generally decrease with
increasing f”. The ratio of the nitrogen-broadening coefficient to the corresponding oxygenbroadening coefficient is correlated with the magnitude of the oxygen-broadening coefficient (the
narrower lines have the larger Nz-to-O2 broadening ratios). The pressure-shift coefficients are
both positive and negative with values in the range -0.008 to +0.008 cm-’ atm-’ ; no significant
correlation with the widths was found. The results are compared with previously reported measurements. 0 1991 Academic Press. Inc.
INTRODUCTION
Accurate measurements of water vapor line broadening and pressure-induced line
shifting are important for a variety of applications, for example, remote sensing of the
Earth’s atmosphere, studies of combustion, and validation of theoretical predictions
by collisional models. A relatively large number of such measurements have been
reported (see Refs. ( 1, 2) for a bibliography of the published studies), but only a few
of the investigations have been devoted to the deuterated species D20 and HDO. To
obtain data on the v2 bands of the deuterated isotopes, we have recorded a series of
0.0053-cm-’ resolution Fourier transform spectra of D-enriched water vapor at low
pressure ( < 1 Torr) and lean mixtures of D-enriched water vapor broadened by nitrogen,
oxygen, and air. In this paper, we report our extensive set of broadening and pressureshift measurements derived for the D2160 v2 band. centered at 1178.379 cm-’ ( 3 ) .
EXPERIMENTAL
DETAILS AND ANALYSIS
The spectra were recorded at room temperature with the Fourier transform spectrometer located in the McMath solar telescope facility on Kitt Peak, near Tucson,
Arizona. The instrument is operated by the National Solar Observatory (NSO). An
173
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of reproduction
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Inc.
reserved.
174
RINSLAND ET AL.
InAs blocking filter covering 550 to 2850 cm-‘, two liquid-helium-cooled As-doped
Si photoconductor detectors, and a glower source heated to approximately 2000 K
were used in the experiment. A signal-to-in-is-noise ratio that increases from about
200 at 1100 cm-’ to 500 at 1400 cm-’ was achieved with a 40-min integration time
per spectrum.
A 1.2 l-m absorption path Pyrex sample cell fitted with a Teflon valve and wedged
potassium chloride windows was used for the recording of the 12 spectra analyzed in
this study. Three different mixtures were prepared by mixing distilled HZ0 with 99.96
at % DzO. A low pressure (G 1.O Torr) spectrum of each mixture was recorded to
obtain accurate zero-pressure line center positions for the determination of the pressureshift coefficients. For the broadening and shift measurements, the low pressure HDO
+ Hz0 + D20 mixtures were diluted with high purity nitrogen, oxygen, or ultra-zero
air. Spectra with each buffer gas were recorded at total sample pressures of about 200,
300, and 400 Ton-; the total HDO + HZ0 + D20 volume mixing ratio was about
0.3% in each mixture.
Sample pressures were measured with Datametrics Barocel 570A-series pressure
transducers with 0 to 10, 0 to 100, and 0 to 1000 Torr pressure heads. The values
were monitored continuously and did not vary by more than 0.2% while recording
each spectrum. Sample temperatures were measured to about kO.5”C or better with
two T-type thermocouples attached to the cell wall. The measured temperatures ranged
from 21.6 to 24.1”C.
The analysis followed the procedures described in several recent papers (4-6) so
that only a brief description is presented here. The method is based on nonlinear leastsquares fitting of short ( l-2 cm-‘) segments of individual spectra assuming a Voigt
line profile shape for each line. The Doppler width assumed in the calculations was
fixed at the value calculated from the mass of the molecule, the wavenumber (cm-’ ),
and the temperature. In all cases, the calculations match the measured spectral line
profiles to the noise level of the data. Therefore, we believe that deviations from the
Voigt shape caused by the Dicke-narrowing effect are not a significant source of error
in the present work.
Initial values for the line positions and intensities were adopted from Table II of
Camy-Peyret et al. (3) for the D20 u2 band lines and from the 1986 HITRAN line
parameters compilation ( 7) for the HDO and HZ0 lines. The initial guess for the
Lorentz-broadening coefficient ofeach line was selected based on the foreign broadening
gas and the lower state J of the transition. The position, intensity, and width of each
observed line were fitted along with parameters corresponding to the level and slope
of the 100% transmission level. Weak, unassigned lines observed in the data were also
included and fitted. The unassigned lines are probably hot band transitions of D2 I60
and HD 160 and v2 band lines of the heavy oxygen substituted isotopic species (e.g.,
HD’*O and D2180).
Figure 1 displays a typical least-squares fit. The selected interval contains D20,
HDO, and H20 lines. The Hz0 line marked in the figure shows both narrow and
broad absorption components. The narrow component originates from residual water
vapor at -0.01 Torr in the vacuum tank enclosing the interferometer. The broad
absorption is produced in the sample cell and in the Nz-purged paths between the cell
and the interferometer and between the cell and the source. Both the narrow and
broad components were modeled in fitting the HZ0 lines in each spectrum. The wave-
175
WIDTHS AND SHIFTS OF Dz“‘0
0.6-0.5--
-
Measured
.
* Calculated
0.44
:
1270.5
:
: : :
1271.0
.
: :
1271.5
Wavenumber
n
:
: : :
1272.0
HO0
:
.
1272.5
(cm-‘)
FIG. 1.Example of a nonlinear least-squares fit to a section of a 0.0053-cm~’ resolution laboratory spectrum
of a sample of 0.27% Hz0 + HDO + D20 in ultra-zero air at a total pressure of 300.5 Torr. The absorption
path and temperature were 1.2 1 m and 22S”C. respectively. The measured and best-fit calculated spectra
(bottom) and the residuals on an expanded vertical scale (top) have been normalized to the highest measured
signal in the fitted interval. Prominent lines of HZO. HDO, and DzO are marked.
length scale was calibrated from measurements of the position of the narrow (low
pressure) component of -30 isolated Hz 160 lines between 1244.1 and 1564.9 cm-‘.
The measured positions were ratioed to standard values (8) to determine a multiplicative factor to calibrate each spectrum. After scaling the measured positions by the
calibration factor, the fitting error, defined as ( CIY~/~)“~ where m is the number of
degrees of freedom and 6, is the measured minus reference calibration line position
(a), was between 4.0 X 10 -5 and 1.1 X 10 m4cm-’ for a spectrum; the small scatter
is an indication of the precision attained in the calibration.
The measured Lorentz widths (cm-‘) at temperature Tderived from each spectrum
have been corrected to the reference temperature of 296 K assuming a T-o.68 temperature dependence. This dependence is an average value derived by Gamache and
Rothman (9) from calculations of temperature-dependent
N*-broadened linewidths
in the H20 pure rotational and u2 bands. Self-broadened HZ0 half-widths are much
larger than corresponding values for air, N 2, and O2 broadening. In this work. we
assumed a value of 4.84 for the ratio of the broadening of D20 v2 band lines by D20
+ HDO + H20 to their broadening by air. This value, which was adopted for all lines,
was selected by averaging four self-to-air broadening ratios calculated from tunable
diode laser measurements in the u2 bands of H2160 and H2’*0 (10). It is close to the
average self-to-air broadening ratio of 5 .O13 +- 0.68 1 determined for 100 water vapor
lines in the 720-nm region ( I I ). The assumed D20 + HDO + H20-to-air broadening
176
RINSLAND ET AL.
ratio of 4.84 was combined with a value of 0.9 for the air-to-nitrogen broadening ratio
( 7, 10-14) in correcting the Nz- and 02-broadened widths for the broadening by D20
+ HDO + H20. Because the water vapor volume mixing ratio in the samples was low
(m-0.3%), the calculated D20 + HDO + Hz0 broadening corrections are small (~2%
of the uncorrected broadening coefficients).
The Lorentz-broadening and pressure-induced line shift coefficients have been determined from least-squares fits to the measured half-widths and positions as a function
of the total sample pressure. The procedure is described, and graphical examples are
presented in Refs. (4-6). Note that temperature corrections have not been applied to
the measured pressure-shift coefficients.
RESULTS AND DISCUSSION
The measured Lorentz-broadening and pressure-shift coefficients are presented in
Table I for the 134 measured DZ160 lines. Broadening and shifting data for all three
buffer gases were obtained for 126 transitions. Columns 1 and 2 list the measured
wavenumber (cm-‘) and the difference between the observed wavenumber and the
calculated value of Camy-Peyret et al. (3), expressed in 1O-3 cm-‘. In all cases, the
difference is less than 1 X 10 -3 cm-’ . Columns 3 to 8 contain the rotational quantum
numbers for the upper and lower states from Ref. (3). The next two columns give the
air-broadening results, the measured Lorentz coefficient b!( air) in cm-’ atm-’ at 296
K, and the pressure-shift coefficient 6’ (air) in I O-4 cm-’ atm-’ at room temperature.
The air-broadening results are followed by the corresponding values for Nz and O2
broadening. Values in parentheses are two times the standard deviation of the fit in
units of the last reported digit; they are a good indication of the random errors in the
measurements (e.g., the effects of instrument noise). The following sources of systematic error have been considered: the temperature corrections to the broadening coefficients, the corrections for the broadening by D20 + HDO + H20, the measured
pressures, the measured temperatures, the wavenumber calibration of the individual
spectra, and zero level offsets in the individual spectra. Our error analysis indicates
that these effects introduce at most only minor biases in the results. Absolute errors
in the broadening and pressure-shift coefficients can be calculated by summing the
errors in Table I with 2% of the measured broadening coefficient and 2 X 10v4 cm-’
atm-’ , respectively.
Figures 2 to 4 illustrate aspects of the measurement results. In Fig. 2, we present
the measured air-broadening coefficients plotted versus the lower state J quantum
number. The measurements depict the well-known general decrease of the pressurebroadening coefficient with J”; this effect has been observed for Hz0 broadened by
various partners (for example, Refs. (15-18)). The measurement indicated with a
solid triangle was derived from analysis of an unresolved doublet, the only such case
included in this study. The two components have been fitted assuming that they have
the same line position and broadening coefficient. Similar to the results of previous
Nz-broadening investigations on Hz0 doublets (for example, Refs. (Z6-19)), we measure broadening coefficients that are unusually narrow.
Figure 3 displays the ratio b?( N2)/b~(Oz) plotted versus bf(O,). A high degree of
correlation between the two quantities is apparent. Assuming a linear relation between
bt( N2)/bi(02)
and bf(Oz), the following expression has been derived from a leastsquares fit to the data (0.024 < bt(O,) < 0.064, in cm-’ atm-’ at 296 K):
WIDTHS AND SHIFTS OF D,“O
177
b:( N2),’ b:( 02) = 3.234 - 23.27!$( 0,).
(1)
Since the scatter among the bF( 02) data at a given J” is also rather small, an alternative
expression has been computed by least-squares fitting our measurements (0 < .I”
< 12):
b:(N,)/b;(Oz)
= 1.756 + 0.0681.I”.
(2)
Equations ( 1) and (2) represent empirical relations that should be useful for estimating
values for transitions similar to those measured in this study. No clear correlation
between the measured broadening coefficients and IL,” was found.
Unfortunately, no other simultaneous nitrogen- and oxygen-broadening measurements have been reported for DzO. However, several such datasets exist for HzO, and
it is interesting to examine them for evidence of the correlation reported above. Grossmann and Browell ( 1 I ) reported nitrogen-to-oxygen broadening ratios and oxygenbroadening coefficients deduced from H20-broadening measurements of 57 lines near
720 nm. The authors noted a correlation between these two quantities (see their Fig.
5) which we find is weaker but otherwise similar to our results (narrower lines have
higher N2-to-02 broadening ratios). A plot of bi(N,)/b?(Oz)
versus #(O,) using
the far infrared pure rotational measurements of Gasster et al. (14) also shows the
same general dependence, and Grossmann and Browell ( 11) noted evidence for this
relation in the theoretical broadening coefficients computed for microwave Hz0 lines
by Bauer et al. (20). However, the v2band Hz0 data of Eng et al. ( 13) show a decrease
rather than an increase in b?_(N2)/bt(Oz) with decreasing @(O,). The reason for
this discrepancy is unclear, but it should be noted that Eng et al. ( 13) included several
very narrow high-J transitions among their sample of seven measured lines. Collisional
narrowing effects, which are likely to be important for such transitions, were not
modeled in their data analysis.
Air-broadening coefficients are related to nitrogen- and oxygen-broadening coefficients by the formula
@(air) = 0.79bF(N2) + 0.21b[(02),
(3)
where 0.79 and 0.2 1 are the relative proportions of nitrogen and oxygen in dry air by
volume. From Eqs. (2) and (3), we calculate an air-to-nitrogen broadening ratio of
0.910 at .I” = 0 declining to 0.872 at .I” = 12. Note that the ratio decreases by only a
factor of 1.04 while bf(Nz)/bt(02)
increases by a factor of 1.46 between J” values
of 0 and 12. The slight decrease in the an-to-nitrogen broadening ratio with increasing
J” can also be noted from a plot (not shown) of the ratios of our measured air-tonitrogen broadening coefficients versus J”. Because the average air-to-nitrogen broadening ratio has often been reported in previous studies, we also calculated the mean
and standard deviation of the ratios deduced from our measured air- and nitrogenbroadening coefficients. The value of 0.891 + 0.023 for our sample of lines agrees
very well with other experimental determinations: 0.897 t 0.022 determined for 21
lines of the v2 band of D20 ( 12), 0.892 + 0.027 determined for 3 1 lines of the v2band
of HDO (lo), 0.885 + 0.024 deduced from 14 lines in the v2 bands of H2160 and
H2”0 (IO), 0.905 + 0.008 from measurements of the line broadening of the v2 band
of H20 ( 13), 0.906 -t 0.00 1 from far infrared measurements of pure rotational Hz0
lines ( 14). and 0.907 & 0.011 computed from measurements in the 720-nm region (11).
178
RINSLAND ET AL.
TABLE I
Air-, N2-, and OrBroadening Coefficients (in cm-’ atm-’ at 296 K) and Pressure-Induced Line Shift
Coefficients (in 10e4 cm-’ atm-‘) for Selected Lines in the Q Band of D2160
v(obs)
O-C J' K; K;
1017.6941-0.6
1030.2833 -0.2
1037.7214 -0.1
1051.0995-0.2
1055.4902 0.1
1063.7910 -0.2
1064.1980 0.0
1065.7524 -0.0
1071.9679 0.0
1072.3719 0.2
1073.2595-0.3
1075.4228 0.2
1075.5324 0.4
1078.1663-0.0
1079.8629 0.0
1086.9724 0.3
1091.6370 0.2
1095.4292 -0.1
1095.9376-0.1
1097.6072 0.4
1100.1918 0.1
1100.7040 0.2
1103.8281 0.3
1106.1758 0.3
1107.5052-0.3
1107.8657 0.2
1112.6969-0.1
1112.9633 0.0
1114.4351 0.4
1114.6901 0.0
1119.8856 0.1
1120.462E-0.2
1123 ::!: -0.1
1123 5136 0.3
1123 5770 0.4
1124.3924 0.3
1124.5596 -0.4
1126.8624 0.0
1127.3766-0.1
1126.6618 -0.1
1128.8236-0.1
1130.1632-0.2
1139.7911 0.2
1141.1169 0.3
1142.6033 0.3
1143.5951 -0.4
1143.7652 0.4
1144.3465 0.1
1144.6230 -0.9
1144.7925-3.0
1148.4367 0.2
1151.0577 0.1
1151.6360 0.2
1152.1620 0.1
1152.4257 0.2
1155.7090 0.2
1156.7325 0.1
1157.2359 0.2
1158.1201 0.2
1159.9520 0.1
1190.2211 0.0
1193.2554 0.1
1194.0383 0.2
1198.5365 0.0
1199.7932 0.1
1206.8541 0.4
12'7.9701-0.0
1209.3861 0.1
1211.3796 0.2
1213.3863 0.1
1214.7653-0.1
1216.6625 -0.2
1217.9211 0.0
1218.7426-0.2
Note :
l:
7
6
6
5
5
4
4
6
5
4
9
9
9
0
4
3
6
7
7
5
2
2
4
6
6
8
10
9
5
7
8
9
8
4
6
9
7
5
4
1
6
6
2
4
5
10
3
5
11
7
1
2
6
3
4
5
3
4
0
3
1
2
2
3
1
3
2
2
4
6
2
5
3
3
4
4
3
3
2
3
3
2
2
2
2
0
1
1
2
2
1
0
1
1
2
2
1
1
2
0
1
2
0
1
2
3
3
0
1
1
3
3
1
1
3
2
0
2
0
3
1
2
3
1
0
1
1
2
0
1
1
1
0
0
1
1
0
1
1
0
2
1
1
2
2
1
1
2
4
2
4
3
4
2
1
4
3
3
6
9
9
7
2
2
5
7
7
4
1
0
3
6
5
8
9
8
5
7
7
7
6
4
6
6
5
2
4
0
3
5
2
2
5
7
3
3
8
6
1
2
5
2
4
4
2
3
0
3
0
1
2
2
1
3
0
2
3
4
1
4
3
2
.?’ K,
K,
0 5 3
7 5 3
7 4 3
6 4 2
6 3 3
5 41
5 4 2
7 3 5
6 3 4
5 3 2
10 1 9
10 1 10
10 0 10
9 2 8
5 3 3
4 31
7 2 6
8 18
8 0 6
6 2 5
3 3 0
3 31
5 2 4
7 0 7
716
817
10 2 6
9 3 7
616
7 2 6
6 3 6
9 4 6
8 4 5
515
6 2 5
9 2 7
7 4 4
5 41
5 0 5
2 2 1
6 4 2
6 3 4
3 13
4 3 1
514
10 4 6
3 2 2
5 3 2
11 4 7
7 2 5
212
3 0 3
6 2 4
4 13
413
5 2 3
3 21
4 2 2
111
3 12
101
2 0 2
111
3 0 3
0 0 0
212
211
10
1
3 2 2
615
212
5 0 5
2 0 2
3 13
be(air)
dO(.ir)
bfCN2,
b"(N2)
0.0774(100) 14(H)
0.0814( 26)
-4( 5)
0.0860( 48)
-6( 3)
0.0631( 15) -lQ( 1)
0.0909( 12) -39(11)
0.0869( 21)
6( 7)
0.0671( 10)
3( 6)
0.0694( 35)
ll(22)
0.0940( 17) 20(41)
0.0992(196) -4(58)
0.0946( 7) -17( 6)
0.1006( 22) -38(17)
0.0957( 39)
7(15)
0.0974( 8)
6( 6)
O.OQlQ( 92)
0.0899( 39)
0.0758(104)
0.0705( 36)
0.0696( 16)
0.0625( 57)
0.0927( 5)
0.0928( 12)
0.0921( 33)
0.0780( 27)
0.0801( 7)
0.0955( 54)
0.0943( 25)
0.0932( 7)
0.0954( 30)
0.084:: 39)
O.O92L( 38)
0.0676( 16)
0.0822( 13)
0.0813( 54)
0.0673( 19j
0.0664( 24)
0.0827( 83)
0.0797( 33)
0.0832( 53)
0.0920( 7)
0.0649( 62)
0.0899( 61)
0.0657( 9)
0.0829( 53)
0.0917( 42)
0.1029( 76)
0.0880( 17)
0.0664( 49)
0.0976( 15)
0.0936( 21)
0.0957( 11)
0.0859(150)
0.0949( 17)
0.0896( 37)
-15( 8)
20(24)
-29(25)
-28(18)
-36( 5)
-2(19)
-9(44)
-6(M)
-11(25)
6( 6)
9(22)
-5(17)
-25(16)
-37( 6)
6( 7)
-6(17)
-13(31)
-22(10)
-3(16)
0.1000( 69)
0.1019( 7.5)
0.0829( 59)
0.0826( 32)
0.0783( 35)
0.0951( 86)
0.1060( 3)
0.1026( 7)
0.1012( 20)
0.0661( 45)
0.0921( 15)
0.1156( 53)
0.1041( 27)
0.1047( 7)
0.1060( 20)
0.0999( 37)
0.1019( 40)
0.0927( 63)
0.0874( 32)
0.0950( 23)
0.1021( 51j
0.0964( 52)
0.0940( 93)
0.0692( 38)
0.0918( 39)
0.1033( 6)
0.0939( 60)
O.OQQl( 69)
0.0990( 17)
0.0975( 13)
0.1010~ 12)
0.1138( 52j
0.0951( 23)
0.0966( 21)
0.1099( 1)
0.1056( 6)
0.1083( 36)
0.0995(163)
0.1062( 21)
0.0997( 86)
-11( 9)
52(23)
-19(20)
-X(12)
-39( 8)
5(10)
-22( 4)
-10(16)
-23(16)
-12(10)
-7(19)
-13(16)
3( 4)
-4( 9)
lO(21)
X(15)
25(21)
1(46)
-25(29)
-16(16)
l(25)
5(35)
-32(56)
-l?(lQ)
-3oc 4)
_14(33)
16(66)
ll(35)
-20(46)
5(lO)
35(14)
-3(25)
-15(42)
-47( 4)
lO( 7)
13(16)
-38(54)
-7( 7)
25(19)
-ll(lO)
-34(15)
-12(14)
-53( 7)
-14(27)
-4( 7)
-54( 5)
-ll( 4)
-46( 7)
0.0986( 4)
0.1076( 46)
0.1075( 26)
0.1035( 10)
0.1032( 44)
0.1071( 26)
0.1057( 22)
0.1079( 12)
0.1072( 16)
-12( 4)
-52( 6)
-2( 7)
-62( 2)
13(20)
-5( 5)
-62(26)
-25(10)
-51( 3)
0.1014( 9) -36( 5)
0.1073( 9)
64i 4)
0.1046( 2)
39( 4)
0.1020( 10) -lO( 7)
0.0969( 23)
40( 4)
0.1024( 26)
63( 3)
4c 41
0.0933( 31)
0.1025( 11) -ii 5j
0.1004( 11) 40( 4)
-1(15)
0.0945( 24)
0.0935( 16) 46( 3)
0.1005( 42) 25( 3)
0.0952( 13) -2(U)
0.0981( 4)
30( 4)
0.0976( 16) 23( 5)
0.1124( 6)
0.1167( 46)
0.1156( 3)
0.1136( 27)
0.1068( 45)
0.1141( 7)
0.1039( 47)
0.1136( 15)
0.1124( 45)
0.1066( 46)
0.1051( 8)
0.1053( 64)
0.1062( 17)
0.1089( 6j
0.106$( 38)
-41( 5)
80(14)
47( 4)
-15( 3)
30(14)
75( 6)
-7( 4)
-13( 7)
49c 6)
-8( 5)
61( 6)
26(14)
-lO( 9)
39( 3)
30(14)
0.0898( 49)
O.lOlQ( 23)
0.0976( 15)
0.0905( 10)
0.0956( 46)
0.0963( 6)
0.0936( 31)
0.0968( 15)
0.0958( 9)
14(16)
-30(14)
-6(16)
-2(35)
-15( 6)
-22(14)
17(13)
-21( 2)
-33( 7)
-14(14)
-lQ( 2)
-18(11)
-9c101
-ii
9;
-15( 2)
-6(13)
-4(10)
17(19)
38(47)
-37(35)
-2oiizj
Transitionbelonging to an unresolveddoublet (see text)
-18(39)
bfCO2)
0.0393( 9)
0.0406( 11)
0.0448( 24)
0.0447( 11)
0.0500( 22)
0.0471( 7)
0.0460( 2)
0.0475( 7)
0.0478( 16)
0.0486( 17)
0.0345( 8)
0.0317( 7)
0.0316( 3)
0.0396( 20)
o.ososi ioj
0.0519( 5)
0.0459( 11)
0.0361( 2)
0.0391( 4)
0.0494( 13)
0.0521( 7)
0.0517( 6)
0.0522( 9)
0.0409( 5)
0.0468( 16)
0.0431( 24)
0.0394( 4)
0.0406( 4)
0.0450( 12)
0.0450( 7)
0.0418( 16)
0.0390( 20)
0.0410( 14)
0.0469( 4)
0.0479( 18)
0.0466( 57)
0.0429( 9)
0.0472( 25j
0.0487( 16)
0.0583( 19)
0.0448( 15)
0.0482( 30)
0.0556( 8)
0.0510( 9)
0.0536( 35)
0.0406( 22)
0.0597( 22)
0.0491( 18)
0.0431( 45)
0.0481( 10)
0.0607( 13)
0.0564( 15)
0.0486< 6)
0.0540( 2Sj
0.0559( 2)
0.0509( 8)
0.0549( 10)
0.0524( 7)
0.0638( 11)
0.0586( 2)
0.061.3( 6)
0.0609( 5)
0.0624( 6)
0.0579( 2)
0.0634( 16)
0.0561( 4)
0.0590( 6)
0.0602( 6)
0.0540( 3)
0.0492( 3)
0.0628( 19)
0.0518( 17)
0.0560( 6)
0.0587( 6)
6O(O2)
-12( 6)
-20(12)
-18(11)
-1st 4)
-27( 4)
-Q( 4)
-13c 3)
-13( 5)
-2( 2)
-29( 7)
-Q( 3)
-28( 3)
-le.(7)
-24( 2)
-5( 2)
-28( 5)
-14( 7)
-22( 2)
-25( 2)
-22( 7)
-22( 2)
-15( 3)
-Q( 4)
-24i 7)
-3( 4)
-II
ii
31
6j
-15(10)
-2si 3j
-4( 4)
-lO( 4)
-lQ(lQ)
-12(16)
-32( 4)
-lO( 5)
-l( 3)
-16( 2)
-Q( 6)
-15( 6)
Q(11)
-16(10)
-25( 6)
-26( 3)
-ll( 6)
2( 5)
-15(11)
-22( 4)
-O(lO)
-41(18)
-a< 4)
-17( 6)
-21( 4)
-26( 3)
6( 1)
-Q( 5)
-25( 2)
-14( 4)
-24( 2)
-18( 6)
-27( 5)
24( 3)
18( 5)
O( 5)
20( 7)
8( 3)
5( 11
-7( 5)
ll( 4)
-SC ‘I
1oi 2j
28(10)
-4( 5)
12( 1)
16( 3)
WlDTHS AND SHIFCS OF D2160
179
TABLE I-Continued
u(obs)
O-C J' K; K;
1219.0064 0.0
1223.6397-0.2
1224.0700 0.1
1224.7298 0.1
1225.9696 -0.1
1227.9939 0.1
1228.3814 0.2
1230.2288 0.1
1230.6939 0.1
1231.0922 0.0
1232.2269-0.0
1233.3856 -0.0
1235.5510-0.1
1238.4464 0.3
1239.0458 0.1
1243.3178 0.3
1243.9096 -0.0
1247.0872-0.1
1247.3153 0.2
1249.5052 0.2
1250.4657 0.4
1258.9669-0.1
1257.9610 0.4
1258.1915-0.3
1261.8311 -0.2
1262.8512-0.2
1266.8145 0.1
1269.1287 0.2
1269.2446 0.0
1269.3372 0 0
1271.2191 0.3
1271.4429-0.5
1271.9607-0.2
1278.1543 0.2
1278.2491 0.3
1280.4476 0.1
1281.7214-0.1
1282.6631 -0.2
1283.1883 -0.3
1285.2359 -0.0
1288.3567 0.0
1292.4536-0.0
1296.9318-0.1
1297.8954 0.2
1300.6097 0.1
1305.9364-0.0
1307.3162 0.2
1309.4913 0.0
1309.5537 -0.2
13?4.4440 0.2
1321.6404 0.1
1322.0745-0.4
1324.0890 -0.5
1324.4418 -0.0
1326.7592 0.1
1343.5829 -0.3
1373.1056 -0.0
1373.3810 -0.1
1425.3878 -0.3
1428.0766 -0.1
4
7
4
8
4
5
6
5
5
4
8
3
3
6
5
6
3
7
7
a
7
8
7
10
7
8
6
9
10
9
8
3
3
10
10
8
9
4
9
4
9
5
10
10
6
11
7
4
4
12
5
5
13
13
12
7
7
7
9
7
7
0
3
2
3
1
3
1
0
2
3
2
3
3
2
3
1
2
2
3
4
0
4
1
2
4
2
2
0
3
1
1
3
3
0
1
;
5
j
1
3
2
3
2
2
3
2
3
4
4
1
4
4
1
2
2
4
5
5
6
7
0
J" K; K,
4
3 1
4
7 2
3
4 1
5
8 2
4
3 0
2
5 2
5
6 0
5
4 1
4
5 1
1
4 2
6
8 1
0
3 2
1
3 2
5
6 1
3
5 2
5
5 2
2
2 1
8
7 1
5
7 2
4
8 3
7
6 1
2
6 3
6
6 2
8 10 1
4
7 3
6
7 3
5
5 1
9
8 1
8 10 2
9
8 0
7
7 2
1
2 2
0
2 2
:C
9 1
::
9 0
7 1
4
9 4
2
3 2
8
8 2
1
3 2
0
6 1
3
4 2
9
9 1
0
9 3
4
5 2
10 10 1
5
6 2
1
3 3
0
3 3
11 11 2
2
4 3
i
4 3
12 12 2
12 12 1
10 11 3
4
6 3
3
6 4
2
6 4
4
8 5
1
6 6
0
6 6
bf(air)
3 0.093?( 3)
5 0.086?( 28)
4 0.0938( 38)
6 0.0896( 31)
3 0.0945( 6)
3 0.0935( 24)
6 0.0929( 47)
4 0.089?( 13)
5 0.0914( 6)
2 0.0959( 41)
7 0.0868( 23)
1 0.0916( 56)
2 0.0971( 13)
6 0.0861( 54)
4 0.0921( 12)
4 0.0913( 13)
1 0.0996( 61
7 0.0852( 29)
6 0.0879( 381
5 0.08?9( 15)
8 0.0850( 13)
3 0.0850( 22)
5 0.0891( 22)
9 0.0?69( 97)
5 0.0880( 44)
5 0.0940( 10)
4 0.0945( 22)
8 0.0?56( 8)
9
8 0.0?63( 6)
6 0.0856( 17)
0 0.0933( 7)
1 0.0927( 13)
9 0.0698( 18)
9 0.0696( 9)
6 0.0852( 34)
5
1 0.096?( 26)
7 0.0803( 16)
2 0.0941( 23)
7 0.0842( 8)
2 0.0943( 13)
8 0.0903( 66)
7 0.0809( 11)
3 O.OQOO( 9)
9
4 0.0956( 20)
0 0.0838( 49)
1 0.084?( 18)
10 0.0603( 22)
1 0.0885( 5)
2 0.0852( 8)
11
11 0.0586( 24)
9
3 0.0865( 19)
2 0.0?25( 31)
3 0.0?41( 39)
3 0.0666( 10)
O*I 0.0542( 25)
l*
d'(0)
be(N2,
d'(N2)
-16( 2)
21( 7)
4( 6)
60(13)
25( 2)
3( 8)
-3( 8)
-3( 5)
9( 3)
-13( 9)
-6( 8)
-27(22)
5c 4)
12(15)
13(11)
-32( 2)
-2O( 4)
16(10)
8( 5)
-56(13)
Q( 5)
-8(11)
-32( 8)
-1?(41)
-5(10)
-13(13)
lO( 9)
ll( 5)
0.1046( 4)
0.09?4( 26)
0.1035( 29)
0.1004( 40)
0.1064( 2)
0.1030( 37)
0.1029( 31)
0.0995( 26)
0.1006( 24)
0.1054( 8)
0.0947( 13)
0.0961( 42)
0.10?2( 12)
0.0948( 38)
0.1029( 15)
0.104?( 7)
0.1119( 13)
0.0950( 24)
0.0994( 13)
0.0969( 59)
0.09?0( 6)
0.095?( 43)
0.1017( 20)
0.0901(126)
0.0986( 23)
0.10?2( 40)
0.1059( 12)
0.0875( 8)
9( 4)
-25( 2)
4( 1)
l?( 3)
2( 2)
2( 7)
31( 6)
0.0674( 6)
13( 2)
0.096?( 12) -23( 3)
0.1023( 53)
33(34)
0.1053( 4)
15( 1)
0.0802( 6)
2( 6)
0.0818( 9)
5( 3)
0.0922( 42)
17(22)
-4( 4)
-3O( 9)
14(10)
8(11)
-21( 6)
-lO( 5)
-53(11)
-?( 2)
0.1042( 19;
3( 9)
0.0891( 15) -40(15)
0.1053( 18)
ll( 3)
0.0945( 13)
9( 8)
0.1064( 17) -12( 2)
0.10?3( 91)
18( 6)
0.0922( 96) -54( 2)
0.0996( 39)
2(13)
5(11)
2(21)
18( 5)
-22( 2)
2( 4)
12( 5)
0.1118( 41) ?6(32)
0.0953( 13) 31(30)
0.0948( 55) 28(15)
0.069?( 11) -23( 6)
0.1009( 6)
3( 5)
0.09?2( 36)
9(1Q)
-5( 9)
15(2?)
-7( 7)
20(51)
-2?(24)
-4O( 6)
0.0645( 17)
-14( 1)
30(14)
9(19)
61(10)
32( 7)
-lO( 2)
-6(10)
-l(ll)
16(10)
-ll(l?)
?(25)
-6(32)
lO(26)
9(52)
16(2?)
-24(44)
-13(41)
43(25)
18(46)
-45(21)
13( 6)
-3(12)
-36( 4)
28(48)
4( 4)
-3( 9)
33( 6)
13( 2)
4(14)
0.1053(126) 21(40)
0.0856( 51) -lO( 9)
0.0812( 75) 35(32)
0.0?82(136) -23(?5)
0.061?( 38) -51( 9)
0.0521( 2)
0.0462( 19)
0.0552( 8)
0.0453( 4)
0.0523( 3)
0.0504( 5)
0.0506( 8)
0.0483( 3)
0.0513i 5j
0.051?( 3)
0.0448( 12)
0.0519( 45)
0.0562( 13)
0.0466( 16)
0.0493( 10)
0.0495( 3)
0.0569( 9)
0.0447( 6)
0.0460( 7)
0.0441( 17)
0.0422( 5)
0.0456( 10)
0.0459( 3)
0.03?4( 91
0.0439( 6;
0.0456( 19)
0.0499( 7)
0.0348( 2)
0.0428( 35)
0.0351( 1)
0.0431( 6)
0.0513( 2)
0.0515( 7)
0.0316( 6)
0.0316( 6)
0.0430( 9‘
0.0397( 5Q,
0.0517( 8,
0.0380( 81
0.0520( 5)
0.0398( 2)
0.0504( 4)
0.03?6( 17)
0.0399( 6)
0.04?3( 6)
0.0316( 4)
0.0485( 20)
0.0435( 8)
0.0443( 4)
0.02761 9)
0.0469i 5j
0.0453( 3)
0.0230( 14)
0.0243( 10)
0.0314( 13)
0.0451( 13)
0.0395( 15)
0.0410( 21)
0.0339( 33)
0.0243( 10)
-3( 1)
-l( 2)
lO( 7)
15( 4)
14( 1)
-l( 6)
-13( 3)
-4c 2)
2( 1)
-4( 1)
-15( 5)
2( 9)
ll( 4)
-4( 8)
5( 31
-14( 3)
-21( 1)
2~ 2j
-5( 5)
-21( 8)
-2( 2)
-12( 3)
-19( 2)
-8(11)
-5i 2;
-lO( 4)
l( 2)
-6( 2)
-28(15)
-5( 2)
-14( 3)
4c 3)
14( 3)
-1:~ 2)
-:I( 1)
3( 2)
38( 5)
-4( 2)
-17( 6)
8( 3)
2( 3)
-ll( 2)
-6( 2)
-21( 5)
-12(11)
-12( 3)
-lO( 4)
lO( 4)
9( 2)
-151 5)
-ii 2;
7( 7)
-23( 4)
-14( 3)
-35Ll)
-13( 21
-7( 3)
-8(11)
-10(15)
-28( 4)
Equation (3 ) can be used to check the consistency of our broadening results. The
mean and standard deviation of the ratio of the measured air-broadening coefficients
to values calculated from Eq. (3) and our bt( N2) and bf( 02) measurements are 1.002
and 0.022, respectively. The good agreement and small scatter between the measured
and calculated air-broadening coefficients demonstrate the internal consistency of our
results.
The only previous experimental measurements of broadening of DzO u2band lines
were reported by Malathy Devi et al. ( 12) based on tunable diode laser spectra. For
the 13 lines in common, the agreement between the two sets of measurements is good;
180
RINSLAND ET AL.
0.12l
G
Single line
A Unresolved
0
2
4
6
8
10
Lower State J Quantum
doublei
12
14
Number
FIG. 2. Measured Lorentz air-broadening coefficients !&air) plotted versus J”. Error bars are two times
the standard deviation of the results. Solid circles denote single lines; the solid triangle represents an unresolved
doublet at 1428.0766 cm-‘.
the ratios and standard deviations (indicated by +) of our experimental broadening
coefficients to those of Ref. (12) are 0.98 ? 0.05 for air broadening and 0.99 + 0.05
for N2 broadening. Unfortunately, no other direct comparisons are possible because
broadening by O2 was not reported in Ref. (12), and to our knowledge, no other
measurements or any theoretical calculations of the widths and shifts of D20 1/Zband
lines have been published.
Figure 4 illustrates graphically the results of the pressure-shift measurements for a
typical spectral line. The calibrated positions derived from the spectra of the low
3.0
0
2.5 --
0
0
2.0 --
0
1.5
0.02
0.03
0.04
$(02)
in cm-‘otm-’
0.05
0.06
at 296 K
FIG. 3. Plot of the nitrogen-to-oxygen broadening coefficient ratio b?(N,)/bL(O,)
ening coefficient bt(02).
versus oxygen-broad-
181
WIDTHS AND SHIFTS OF Dz”O
Jk3
Ko’=O
Kc’=3
c
J”=3
Ko”=l
Kc”=2
Line of D2160
1159.953
Shift Coefficient
in cm-‘otm-’
SO(N,)=-0.0041+0.0005
,^
1159.952
‘S.,
6°(oir)=-0.0036f0.0005
. . ..__
.“-fi ..______
- .‘_.
. . . .._____
-4. .
-./_.___
-- -- -.
. ..__-..___.
._._. _;.
..I___
..-.____
-. -_ Xc
-_
.
.
.-__
l.
-.
_.
h---_.
“,‘_r. .._..___
-.‘=_,
ii
y
SO(O,)=-0.0027+_0.0005
--n.
‘“+.__..
I
1159.951 --
._0
.z
m
r? 1159.950
--
9 Pure
l
Air
-._
A N2
1159.949.
‘02
0.0
0.4
0.2
Total Pressure
0. 6
(otm)
FIG. 4. Plot of calibrated line position versus total sample pressure for a spectral line of D2160. The
quantum assignments for the transition are given at top. The short dashed line shows the best-fit to the data
from the low pressure samples (solid square) and the 02-buffered samples (solid triangles), the medium
dashed line shows the best-fit to the data from the low pressure samples (solid square) and the N2-buffered
samples (open triangles), and the long dashed line shows the best-fit to the data from the low pressure
samples (solid square) and the air-buffered samples (open triangles). The quoted errors are 20 statistical
uncertainties from the fit.
pressure DzO + HDO + Hz0 samples and the samples buffered with Nz, OZ. and air
are plotted as a function of total sample pressure. The dashed lines show the leastsquares fits to the data; the ordinate intercept and slopes of the dashed lines correspond
to the unshifted line position and the pressure-shift coefficients, respectively.
Figure 5 presents the measured pressure-shift coefficients in air plotted versus J”.
A nearly equal number of positive and negative shifts can be noted, and there is no
obvious J-dependence in the shifts. The pressure-shift results for N2 as a buffer gas
are very similar to the results for air; however, most of the pressure-shift coefficients
in O2 are slightly negative (about 75% are less than zero). The means and standard
deviations of the pressure-shift coefficients are respectively +O.OOOl -t 0.0028 for N1
broadening, -0.0004 -t 0.0023 for air broadening, and -0.0008 & 0.0014 for O?
broadening (in units of cm-’ atm-‘). All of the measured shift coefficients are in the
range -0.008 to to.008 cm-’ atm-’ . Seven of the eight HZ0 v2 band measurements
of pressure shifts in air or nitrogen reported by Kelley et al. (21) are negative.
It is interesting to contrast our pressure-shift results with the extensive set of HZ0
shift measurements reported by Grossmann and Browell ( I1 ) . Air, nitrogen, oxygen.
and argon were used as the buffer gases in their experiments. Distinct differences can
be noted, for example: ( 1) the pressure-shift coefficients in Ref. ( 11) are all negative
whereas we observed a nearly equal number of positive and negative shifts; ( 2) the
magnitudes of the pressure-shift coefficients reported in Ref. ( 12) are significantly
larger than the ones obtained in this study; and (3) the apparent linear relation between
the widths and shifts found in Ref. (If) is not apparent in our results. Although our
182
RINSLAND ET AL.
0.015
I
O.OlO--
A
‘;
,E
0.005
I
1
:
I
0
E
‘;3
-0.005
-0.000 &_
0
a
_
i-
_/_!_jj__*_<-_7
Lo
-0.010
--
-0.015)
:
0
:
2
:
I
4
:
:
:
6
:
6
Lower State J Quantum
:
:
10
:
I
12
:
14
Number
FIG. 5. Plot of pressure-shift coefficient in air do (air) versus J”. Error bars are two times the standard
deviation of the results.
experimental values refer to D20 and Grossmann and Browell (II) measured HzO,
the important differences noted above indicate strong vibrational dependences for
Hz0 and D20 pressure shifts in air, N2, and Oz. Recent theoretical work (22) has
been successful in reproducing the N2-, 02-, and air-induced line shift coefficients
measured by Grossmann and Browell ( 1 I ) .
CONCLUSIONS
Air-, nitrogen-, and oxygen-broadening coefficients and pressure-shift coefficients
have been measured for 126 lines of the u2 band of D2160. The results represent the
most extensive set of experimental broadening coefficients reported thus far for D20
and are the only data on the pressure shifts of D20 lines. We have pointed out a
number of interesting aspects of the dataset, for example, the anomalously small
broadening coefficients measured for an unresolved doublet and a strong correlation
between the nitrogen-to-oxygen broadening ratio and the oxygen-broadening coefficient
(narrower lines have higher ratios). Our measured air- and N2-broadening coefficients
are in good agreement with the only previous published measurements ( 12). We hope
that our measurements will prove useful for the calculation of the transfer of radiation
through deuterated water vapor mixtures and the validation of predictions by collisional
models.
ACKNOWLEDGMENTS
The authors thank Claude Plymate and Jeremy Wagner of NSO for their help with the experiment, Greg
Ladd for the computer processing of the data at NSO, Carolyn H. Sutton of ST Systems Corporation for
assistance in processing of the spectra at NASA Langley, and Robert A. Toth of the Jet Propulsion Laboratory
for sending us his calculated Hz160 Y*band line positions to calibrate our spectra. Research at the College
of William and Mary was supported under Cooperative Agreements NCCI-80 and NCCI-43 with NASA.
NSO is operated by the Association of Universities for Research in Astronomy, Inc., under contract
with NSF.
RECEIVED:
July 5, 1991
WIDTHS AND SHIFTS OF D2160
183
REFERENCES
1. M. A. H. SMITH,C.P. RINSLAND,B. FRIDOVICH,AND K. NARAHARIRAO, in “Molecular Spectroscopy:
Modern Research” (K. Narahari Rao, Ed.), Vol. 3, Chap. 3, Academic Press, Orlando, 1985.
2. M. A. H. SMITH, C. P. RINSLAND,V. MALATHY DEVI, L. S. ROTHMAN. AND K. NARAHARI RAO, in
“Spectroscopy of the Earth’s Atmosphere and Interstellar Molecules” (K. Narahari Rao and A.
Weber. Ed%). in press, 199 1.
3. C. CAMY-PEYRET,J.-M. FLAUD,A. MAHMOUDI,G. GUELACHVILI,ANDJ. W. C. JOHNS,ht. J. I@ued
Millimeter Waves 6, 199-233 ( 1985).
4. C. P. RINSLAND,V. MALATHY DEVI, M. A. H. SMITH, AND D. C. BENNER,Appl. Opt. 27, 631-65 1
(1988).
_5. V. MALATHY DEVI, D. C. BENNER,M. A. H. SMITH, AND C. P. RINSLAND,Appl. Opt. 30, 287-304
(1991).
6. M. A.H. SMITH,C.P.RINSLAND,
ANDV.MALATHY
DEVI,J.Mol. Spectrosc. 147, 142-154(19Yl).
7. L.S. ROTHMAN,R. R.GAMACHE, A.GOLDMAN, L.R. BROWN,R.A.ToTH, H. M. PICKETT,
R. L.
POYNTER,J.-M. FLAUD,C.CAMY-PEYRET,A.BARBE,N.HUSSON,C.P.RINSLAND.ANDM.A.H.
SMITH,Appl. Opt. 26,4058-4097
(1987).
8. R. A. TOTH, J. Opt. Sot. Am. B, in press ( 1991).
9. R. R. GAMACHE, AND L. S. ROTHMAN, J. Mol. Spectrosc. 128,360-369 ( 1988).
10. V. MALATHY DEVI,D. C. BENNER,~. P.RINSLAND.M. A. H. SMITH,AND B. D. SIDNEY.J. .Mol.
Spectrusc. 117, 403-407 (1986).
11. B. E. GROSSMANN AND E.V. BROWELL,J. Mol. Spectrosc. 138, 562-595 (1989).
I_‘. V. MALATHY DEVI,C.P.RINSLAND,D. C. BENNER,AND M. A. H. SMITH,Appl. Opt. 25, 336-338
(1986).
13. R.S. ENG, P. L. KELLEY.A. R.CALAWA.T.C. HARMAN,AND K. W.NILL.MOI. Ph.vs. 28.653-664
(1974).
14. S. D. GASSTER.C. H.TOWNES, D.GOORVITCH,AND F.P.J.VALERO.J. Opt. Sot. Am. ES, 593-601
(1988).
15. J.-Y. MANDIN, J.-M. FLAUD,C. CAMY-PEYRET,AND G. GUIXACHVILI.
J Quant. Spectrosc. Radial.
Transfkr 23, 351-370 (1980).
16. J.-Y. MANDIN, C. CAMY-PEYRET.J.-M. FLAUD, AND G. GUELACHVILI,
Can.J. Phys. 60. 94-10)
(1982).
17. J.-Y. MANDIN, J.-P. CHEVILLARD,
J.-M. FLAUD,AND C. CAMY-PEYRET,J Mol. Spectrosc. 132. 352360 (1988).
18. J.-Y. MANDIN, J.-P. CHEVILLARD,
J.-M. FLAUD,ANDC.CAMY-PEYRET, J. Mol. Spectrosc. 138,430439 (1989).
19. J.-Y. MANDIN, J.-M. FLAUD,AND C. CAMY-PEYRET,J. Quant. Spectrosc. Radiat. Transfer 26. 483494(1981).
20. A. BAUER,M. GOM)N, M. KHEDDAR, AND J.M. HARTMANN, J. Qunnt. Spectrosc. Radiat. Tran.xtkr
41,49-54
(1989).
21. P. L. KELLEY.R. A. MCCLATCHEY, R. K. LONG, AND A. SNELSON,Opt. Quant. Electron. 8, I 17-144
(1976).
22. B.E. GROSSMANN,E.V.BROWELL,
A.D.Bv~0v.v.
A.KAPITANOV, V.V. LAZAREV,YU. N.PoNOMAREV,L.N.SINITSA,E.A.KOROTCHENKO,V.N.STRO~NOVA,AND
B.A.TIKHOMIROV.
Atlno.s
Opt. 3,617-630
(1990).

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