FTIR Emission Spectra and Molecular Constants for DCl

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Journal of Molecular Spectroscopy195,185–191 (1999)Article ID jmsp.1999.7824, available online at http://www.idealibrary.com on

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FTIR Emission Spectra and Molecular Constants for DCl

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HCl is an important gas which is used as an absolute wavenumber stnd has been used in studies of the breakdown of the Born–Oppenpproximation (1–3). Recently, HCl was observed in the infrared region inpper atmosphere (4) and in the IR absorption spectra of the atmosphereenus (5) and an S-type star (6).The HCl fundamental has previously been measured in absorption by

t al. (7) and Guelachviliet al. (8), as well as by Rinslandet al. (9) during aecent experiment on room temperature HCl. Measurements on hot HCeen reported by Webb and Rao from absorption spectra (10) and by Le Blanct al. and Claytonet al. from emission spectra (11, 12). The pure rotationa

ines were measured by tunable far-infrared spectrometry (13, 14) and subillimeter-wave techniques (15, 16). A set of Einstein A coefficients were al

alculated for HCl (17).While spectra of both the fundamental and hot bands of HCl are kn

here are no measurements available for the hot bands of DCl. Absopectra of the fundamental were recently measured by Klee and Ogilvie18).ther previous studies of DCl include measurements of the fundamenuelachviliet al. (8) and of the fundamental and overtone bands by Webbao (10). Pure rotational spectra of DCl were observed by Fusinaet al. (19)ith a tunable far-infrared spectrometer, and by Klauset al. (16) by submil-

imeter-wave techniques.We report here new high-resolution infrared emission spectra of DCl.

pectrum was accidentally observed while we were trying to measurnfrared spectrum of DBO (20). It was recorded with a Bruker IFS 120 Hourier transform spectrometer. Solid boron and calcium chloride in a tanoat were heated to 1000°C in a tube furnace, while D2 gas was passed throu

he tube at a pressure of 50 Torr. The emission spectrum was recordeesolution of 0.01 cm21 over the 1600–2900 cm21 range, using a KBeamsplitter and an HgCdTe detector. The reaction between D2 and calciumhloride gave DCl as a product.Vibration–rotation line positions of thev 5 13 0, 23 1, 33 2, and 43bands of D35Cl, and of thev 5 13 0, 23 1, and 33 2 bands of D37Clere measured. For the more intense bands, strong unblended lineeasured to an estimated precision of60.0002 cm21, while for the weakerv33 2 andv 5 43 3 bands, the typical uncertainties for unblended l

ere60.0004 and60.002 cm21, respectively.Our measured line positions are reported in Table 1A for D35Cl and Table

B for D37Cl.1 The signal-to-noise ratio for the strongest lines was better5. The spectral analysis to determine the line positions was carried outC Decomp, a program developed by J. W. Brault. The rovibrationalere calibrated with CO lines, which were present as an impurity inpectrum. The CO line positions were taken from the book by Maki and W21). For completeness, Tables 1A and 1B also list the literature data uhe present fits.

As the next stage of our analysis, separate sets of band constantetermined for D35Cl and D37Cl. The input to these fits consisted of the n

1 The data used in the present analysis may also be obtained electrorom authors RJL ([email protected]) or PFB (bernath@UWaterloo.

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esults reported here plus pure rotational (16, 19) and rovibrational (18)easurements from the literature, with all line positions being weighted b

nverse square of their estimated uncertainties. These data sets for D35Cl and37Cl were fitted to the familiar band constant expression (22)

E~v, J! 5 Tv 1 Bv @ J~ J 1 1!# 2 Dv @ J~ J 1 1!#2 1 Hv @ J~ J 1 1!#3 1 . . . ,

[1]

here Tv is the vibrational energy, and Bv , Dv , Hv , . . . etc. are the usunertial rotation and centrifugal distortion constants. The constants obtrom these fits are reported in Table 2.

A combined isotopomer analysis was then performed using the DCl daescribed above, together with analogous high-quality literature data for35Clnd H37Cl. This was done both in order to determine Born–Oppenhereakdown correction terms for this system and because this combinedsis allows us to obtain more extensive and reliable DCl constants thanetermined from the data for each isotopomer considered alone. In part

he FTIR HCl measurements (9, 11) include data for levels up tov (HCl) 5 3,hile the usual first-order semiclassical scaling relationship (22–24) shows

hat the present DCl results only span the energy range up tov (HCl) ' 2.72or D35Cl and tov (HCl) ' 2.01 for D37Cl. Similarly, the highest observedJevel in the HCl data used isJ(HCl) 5 31, while semiclassical scaling shohat the highest DCl rotational level observed here (J(DCl) 5 35) corre-ponds toJ(HCl) ' 24.95. Thus, DCl constants yielded by this combinsotopomer analysis will be valid for a wider range of energy than is spay the DCl data itself.Following Ref. (25), transitions of isotopomera of speciesA–B formed

rom atoms of massMAa and MB

a are expressed as differences betweennergies written as

Ea~v, J! 5 O~l,m!Þ~0,0!

Y l,m1 Sm1

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~v 1 1/ 2! l@ J~ J 1 1!#m

1 O~l,m!$~0,0!

HDMAa

MAa d l,m

A 1DMB

a

MBa d l,m

B JSm1

maDm1l/ 2

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3 ~v 1 1/ 2! l@ J~ J 1 1!#m,

herema is the usual atomic reduced mass of isotopomera, DMAa 5 MA

a 2

A1, anda 5 1 identifies a selected reference species, in this case the

bundant isotopomer,1H35Cl. The semiclassical and Born–Oppenheireakdown correction coefficientsd l ,m

A determined here are simply relatedhe older WatsonD correction parametersD l ,m

A 5 2d l ,mA MA

1(m1)m1l / 2/Ul ,mme

25). The conventional Dunham constants for minority (a Þ 1) isotopomerre readily generated from the expression

Y l,ma 5 HY l,m

1 1DMA

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a

MBa d l,m

B JSm1

maDm1l/ 2

. [3]ally

0022-2852/99 $30.00Copyright © 1999 by Academic Press

All rights of reproduction in any form reserved.

186 NOTE

TABLE 1AD35Cl Line Positions (in cm21), Uncertainties,a and the Differencesa

from Predictions Yielded by the Constants of Table 3

Copyright © 1999 by Academic Press

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187NOTE

The results obtained on performing a simultaneous fit to the present35Clnd D37Cl data sets and to analogous high-quality literature infrared (9, 11) andicrowave (16) data for HCl using Eq. [2] are presented in Table 3. Thesere performed with atomic masses taken from the 1993 mass table (26), usingrogram DSParFit (25), which uses a sequential rounding and refitting prure to minimize the numbers of significant digits required to accurepresent the data (27). The “All-Isotopomer Fit” H35Cl column in Table 3resents the results of this simultaneous fit to all 292 HCl and 360 DCl

or the user’s convenience, parameter sets for the minority isotopomerrated from the former using Eq. [3] are presented in the last three colum

his table. Note that our definition of the reference isotopomer means thaDMAa

0 for both atoms of H35Cl, so the level energies of all four isotopomers me generated from the Yl ,m

a parameters alone. The dimensionless standard27) for this combined isotopomer fit iss# f 5 0.985, which means that overage, predictions yielded by the fitted constants agree with the experiata to within 0.985 times the estimated experimental uncertainties. Ts# f

alues shown for the minority isotopomers were obtained by comparin

TABLE 1A

a Relative to last digit of the observation.b From Ref.16.c Ref. 19.d Ref. 18.

Copyright © 1999 by

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xperimental data with predictions generated using the listed (derived) {l ,m}onstants for these species. For D35Cl and D37Cl, theses# f values are especialquivalent to those (1.171 and 0.855, respectively) associated with theendent band constant fits summarized in Table 2.While not shown, the correlated uncertainties in the DCl paramete

able 3 are all roughly [m(H35Cl)/m(DCl)] l1m/2 times those shown for thorresponding H35Cl parameters. Because of the improved statistics aiated with the fit to the larger data set, these are substantially smallehe analogous uncertainties obtained in Dunham expansion fits to thor one isotopomer at a time, while the quality of fit is essentially the soreover, because of the greater range ofv andJ associated with the HCata, the DCl parameters obtained from the combined isotopomer an

nclude higher order vibrational and rotational expansion constantsould be reliably obtained from independent analyses of the D35Cl and35Cl data. Thus, the DCl band constants recommended here arealculated from the expansion coefficients in Table 3, rather thanndependent-fit results shown in Table 2.

Continued
—
Academic Press

188 NOTE

TABLE 1BD37Cl Line Positions (in cm21), Uncertainties,a and the Differencesa

from Predictions Yielded by the Constants of Table 3


189NOTE

TABLE 1B—Continued

a Relative to last digit of the observation.b From Ref.16.c Ref. 19.d Ref. 18.

nificant

TABLE 2Band Constants from Independent Fits to Data for X1S1 State D35Cl

(Upper Entries) and D37Cl (Lower Entries)

Note.The numbers in parentheses are the 95% confidence limit uncertainties in the last sigdigits shown.


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190 NOTE

ACKNOWLEDGMENTS

We thank Dr. Pina Colarusso for recording the spectrum. This workupported by the Natural Sciences and Engineering Research Couanada (NSERC).

REFERENCES

1. J. F. Ogilvie,J. Mol. Spectrosc.128,216–220 (1988).2. J. A. Coxon,J. Mol. Spectrosc.133,96–115 (1989).3. J. A. Coxon and P. G. Hajigeorgiou,J. Mol. Spectrosc.139, 84–106

(1990).

TABParameters for X1S1 State HCl and

652 High-Resolution Infrared and MicEq. [2]

Note. The numbers in parentheses aresignificant digits shown.


sof

4. C. B. Farmer, B. Carli, A. Bonettie, M. Carlottie, B. M. Dinelli, H. FaW. F. J. Evans, N. Louisinard, C. Alamichel, W. Mankin, M. Coffey, I.Nolt, D. G. Murcray, A. Goldman, G. M. Stokes, D. W. Johnson, WTraub, K. V. Chance, R. Zander, G. Roland, and L. Delbouille,J. AtmosChem.10, 237–273 (1990).

5. W. S. Benedict, J. Connes, P. Connes, and L. D. Kaplan,Astrophys. J.147,1230–1237 (1967).

6. S. T. Ridgeway, D. F. Carbon, D. N. B. Hall, and J. Jewell,Astrophys. JSuppl.54, 177–209 (1984).

7. D. H. Rank, B. S. Rao, and T. A. Wiggins,J. Mol. Spectrosc.17,122–130(1965).

8. G. Guelachvili, P. Niay, and P. Bernage,J. Mol. Spectrosc.85, 271–281(1981).

3l Obtained from a Simultaneous Fit ofave Data for All Four Isotopomers to

e 95% confidence limit uncertainties in the last

LEDCrow

th

Academic Press

. C.

11

1 H.

1 gs

1 .

1

1

1

11 .

2 ta,

2 romas

2 nto,

22222

el

G

UWN

E

ona8

191NOTE

9. C. P. Rinsland, M. A. H. Smith, A. Goldman, V. Malathy Devi, and DBenner,J. Mol. Spectrosc.159,274–278 (1993).

0. D. U. Webb and K. N. Rao,J. Mol. Spectrosc.28, 121–124 (1968).1. R. B. Le Blanc, J. B. White, and P. F. Bernath,J. Mol. Spectrosc.164,

574–579 (1994).2. C. M. Clayton, D. W. Merdes, J. Pliva, T. K. McCubbin, and R.

Tipping, J. Mol. Spectrosc.98, 168–184 (1983).3. I. G. Nolt, J. V. Radostitz, G. Di Lonardo, K. M. Evenson, D. A. Jennin

K. R. Leopold, M. D. Vanek, L. R. Zink, A. Hinz, and K. V. Chance,J.Mol. Spectrosc.125,274–287 (1987).

4. P. De Natale, L. Lorini, M. Inguscio, G. Di Lonardo, and L. Fusina,ChemPhys. Lett.273,253–258 (1997).

5. F. C. DeLucia, P. Helminger, and W. Gordy,Phys. Rev. A3, 1849–1857(1971).

6. Th. Klaus, S. P. Belov, and G. Winnewisser,J. Mol. Spectrosc.187,109–117 (1998).

7. E. Arunan, D. W. Setser, and J. F. Ogilvie,J. Chem. Phys.97,1734–1741(1992).

8. S. Klee and J. F. Ogilvie,Spectrochim. Acta A49, 345–355 (1993).9. L. Fusina, P. De Natale, M. Prevedelli, and L. R. Zink,J. Mol. Spectrosc

152,55–61 (1992).0. Y. Kawashima, P. Colarusso, K. Q. Zhang, P. Bernath, and E. HiroJ.

Mol. Spectrosc.192,152–161 (1998).1. A. G. Maki and J. S. Wells, “Wavenumber Calibration Tables f

Heterodyne Frequency Measurements,” U.S. Govt. Printing Office, Wington, DC, 1991.


,

h-

2. G. Herzberg, “Spectra of Diatomic Molecules,” Van Nostrand, Toro1950.

3. J. L. Dunham,Phys. Rev.41, 713–720 (1932).4. J. L. Dunham,Phys. Rev.41, 721–731 (1932).5. R. J. Le Roy,J. Mol. Spectrosc.194, in press.6. G. Audi and A. H. Wapstra,Nucl. Phys. A565,1–65 (1993).7. R. J. Le Roy,J. Mol. Spectrosc.191,223–231 (1998).

Treana ParekunnTsuyoshi HiraoRobert J. Le RoyPeter F. Bernath2

uelph-Waterloo Centre for Graduate Workin Chemistry and Biochemistryniversity of Waterlooaterloo, Ontario2L 3G1, Canada

-mail: [email protected]

Received October 19, 1998; in revised form January 27, 1999

2 Also at: Department of Chemistry, University of Arizona, Tucson, Ariz5721.

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FTIR Emission Spectra and Molecular Constants for DCl