Abstract book - Prof. Per Jensen, Ph.D. - Bergische Universität ...

150 Poster session, H37Hydrogen Sulphide: Dipole Moment Surface and Room TemperatureSpectrumAla’a Azzam 1 , Sergei N. Yurchenco 2 , Jonathan Tennyson 31 UCL, UK, ala'a.azzam.10@ucl.ac.uk; 2 UCL, UK, s.yurchenko@ucl.ac.uk; 3 UCL, UK,j.tennyson@ucl.ac.ukAzzam A.Yurchenko S.N.Tennyson J.Hydrogen sulphide is a triatomic asymmetric top molecule, one of the systems to bestudied as part of the ExoMol project (www.exomol.com). Our ultimate goal is toproduce an accurate and comprehensive list of line positions and intensities for thismolecule applicable for a large range of temperatures (up to 2000K). This will providean important resource for atmospheric modelling of extrasolar planets and cool stars aswell as for the laboratory investigations and pollution studies. In this contribution wepresent a room temperature spectrum of H 2 S based on our new ab initio dipole momentsurfaces (DMS) computed at different levels of theory. The DVR3D 1 program suite wasused to calculate the bound ro-vibration energy levels, wavefunctions, and dipoletransition intensities employing the empirical potential energy surface (PES) 2 which wasfurther refined by fitting to the existing experimental data.The quality of the shallow-shaped DMS of H 2 S in the vicinity of the equilibrium isknown 3 to be critical for computing accurate intensities of the weak asymmetricstretching bands. In this work a systematic ab initio study of DMS of H 2 S is presented.We tested the CCSD[T], CCSD(T)-f12, MRCI methods in conjunctions with differentbasis sets (up to the 5Z-quality) and different corrections at a large range of geometriesas implemented in the MOLPRO program. We observed that unlike the ab initio DMSof water 4 the relativistic corrections and core-valence effects to the DMS of H 2 S do notcancel but add together and thus represent important contributions to the ab initio dipolemoment of hydrogen sulphide.This work is supported by ERC Advanced Investigator Project 267219. Ala'a Azzamthanks the University of Jordan for the financial support.References[1] J. Tennyson, M.A. Kostin, P. Barletta, G.J. Harris, O.L. Polyansky, J. Ramanlal, andN.F. Zobov. Comput. Phys. Commun. 163, 85, 2004[2] V.G. Tyuterev, S.A. Tashkun, and D.W. Schwenke. Chemical physics letters 348,223, 2001[3] T. Cours, P. Rosmus, and V.G. Tyuterev. J Chem. Phys. 117, 223, 2002[4] L. Lodi, J. Tennyson, and O.L. Polyansky. J. Chem. Phys. 135, 034113, 2011