“Global Fit” of the high resolution infrared data of D 2 S and HDS molecules O. N. Ulenikov, E. S. Bekhtereva Physical Chemistry, ETH-Zurich, CH-8093 Zurich, Switzerland An Wen Liu, L. Wan, L.-Y. Hao, Shui-ming Hu USTC, Hefei China J.-M.Flaud LISA, Universite Paris 12, Creteil cedex, France G. A. Onopenko, O.V.Gromova Laboratory of Molecular Spectroscopy, Tomsk State University, Tomsk , Russia

Motivations 1.Study of high resolution spectra of hydrogen sulfide and its deuterated species in new spectral region for applications in physics, chemistry, environmental problems, etc. 2.The main problem of vibration-rotation spectroscopy is a determination of correct PES of a molecule:

Motivations 1.Study of high resolution spectra of hydrogen sulfide and its deuterated species in new spectral region for applications in physics, chemistry, environmental problems, etc. 2.Main methods of determination PES a). Ab initio calculations: R.Marquardt, M. Quack, J. Phys. Chem. A108 (2004) H. Partridge, D.W.Schwenke, J. Chem. Phys. 106 (1997) T. J. Lee, J. M. L. Martin, P. R. Taylor, J. Chem. Phys. 102 (1995) b). Variational methods: P. Jensen, J. Chem. Soc. Faraday Trans. 128 (1988) X.-G. Wang, T. J. Carrington, J. Chem. Phys. 119 (2003)

Motivations 1.Study of high resolution spectra of hydrogen sulfide and its deuterated species in new spectral region for applications in physics, chemistry, environmental problems, etc. 2.Testing of "Global Fit" procedure's possibilities and peculiarities on the base of D 2 S and HDS.

What is the “Global Fit” procedure? (“global fit” parameters) 3. “Effective Hamiltonian” parameters: they describe rotational structure of one isolated vibrational state (polyad of interacting states). 1. Parameters of PES of a molecule: they allow one to describe ro-vibrational structures of any isotopic species of a molecule in a separate electronic state. 2. “Global Fit” parameters: they describe ro-vibrational structure of any vibrational state of one isotopic modification is a separate electronic state.

Asymmetric top molecules 1. Vibrational, rotational, any kind of centrifugal parameters : 2. Resonance interaction parameters (XYZ molecule, C s symmetry) 3. Resonance interaction parameters (XY 2 molecule, C 2V symmetry)

Overview transmitted spectrum of D 2 S Experimental conditions

Small portion of the high resolution spectrum of D 2 S in the region of the bands 2v 1 ( ),v 1 +v 3 ( ), and 2v 3 ( )

Studied ro-vibrational bands 1.v 1, v 2, v 3 : C. Camy-Peyret, J.-M. Flaud, A. N’Gom, J. W. C. Johns, Mol. Phys. 65 (1998) v 1 +v 2, v 2 +v 3 : O. N. Ulenikov, R. N. Tolchenov, M. Koivusaari, S. Alanko, R. Anttila, J. Mol. Spectrosc. 170 (1995) D 2 S molecule HDS molecule 1.v 2 : C. Camy-Peyret, J.-M. Flaud, A. N’Gom, J. W. C. Johns, Mol. Phys. 67 (1989) v 3, v 1 +v 2, v 1, 2v 1, v 2 +v 3, 2v 2, 3v 2 : O. N. Ulenikov, G. A. Onopenko, S. Alanko, V.-M. Horneman, M. Koivusaari, R. Anttila, J. Mol. Spectrosc. 189 (1998) v 3, 3v 3, v 2 +2v 3, v 2 +3v 3 : A-W Liu, B. Gao, F. Qi, S.-M. Hu, J. Mol. Spectrosc. 232 (2005)

Statistical information on the investigated bands of D 2 S

Statistical information on the investigated bands of HDS

20 bands 2965 upper ro-vibrational energies 9700 experimental lines J max =23 K a max = fitted parameters (9 interaction parameters) RMS close to experimental uncertainties Results of the “Global Fit” 22 bands 3670 upper ro-vibrational energies 9800 experimental lines J max =25 K a max = fitted parameters (45 interaction parameters) RMS no worse than experimental uncertainties HDS D2SD2S

Conclusion 1.Fourier transformed spectra of the D 2 S and HDS molecules wre recorded with a high resolution in the region of 2300 – 7000 cm -1 with a Bruker IFS 120 HR in Hefei, China. As the result, 17 new bands of D 2 S and 8 new bands of HDS were found in the spectra with ro-vibrational transitions corresponding J max = 23 and K a max = Global fit ro-vibrational analysis of both isotopic species was made, and set of 370 parameters was obtained which reproduce values of more than 6600 initial experimental energy levels (about transitions in both species) with accuracies close to experimental uncertainties.

Outlook The final step of the present study: joint global fit of all known ro-vibrational experimental data of the H 2 S, HDS, and D 2 S isotopic species and determination of precise potential energy surface of hydrogen sulfide.