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

Poster session, J26 189ExoMol: molecular line lists for astrophysical applications. Atheoretical line list for nickel hydride.Lorenzo Lodi 1 , Sergey N. Yurchenko 1 , Andrew Kerridge 2 , Jonathan Tennyson 11 University College London, Dept of Physics & Astronomy, Gower St., London WC1E6BT, UK2 University College London, Dept of Chemistry, 20 Gordon St., London WC1H 0AJ, UKLodi L.Yurchenko S.N.Kerridge A.Tennyson J.ExoMol (www.exomol.com) is a database of molecular line lists which can be used forspectral characterisation and simulation of astrophysical environments such asexoplanets, brown dwarfs, cool stars and sunspots 1 .New line lists for about 30 small molecules of astrophysical interest which currentlylack a complete spectroscopic coverage are being generated.The list includes diatomics (e.g., C 2 , O 2 , AlO), triatomics (e.g., H 2 S, C 3 , SO 2 ),tetratomics (e.g., PH 3 , HOOH, H 2 CO) and a few larger molecules (most notably CH 4and HNO 3 ).We report progress on a new theoretical line list for nickel hydride NiH. The spectra oftransition-metal hydrides such as NiH are very complicated due to the large-number oflow-lying electronic states, to the importance of correlation, relativistic and spin-orbiteffects and of the various couplings between angular momenta.In particular, the three lowest electronic states form a strongly perturbed system whichso far has been studied using the semi-empirical `supermultiplet' model by Gray et al 2 .Recently 3 new experimental data has become available extending to higher-energyelectronic states, which cannot be modelled properly by semi-empirical models.In our study potential energy curves and the relevant couplings were computed abinitio and the corresponding coupled-surface ro-vibronic problem was solved using anin-house computer program based on expansion in Hund's case (a) wave functions.Potential curves and couplings were then refined semi-empirically using the availableexperimental spectroscopic data.References[1] J. Tennyson and S. N. Yurchenko, Mon. Not. R. Astron. Soc. (submitted).ArXiv:1204:0124[2] J. Gray, M. Li and R.W. Field, J. Chem. Phys. 92, 7164 (1991).[3] Vallon R., S.H. Ashworth, P. Crozet, R.W. Field, D. Forthomme, H. Harker, C.Richard and A.J. Ross, J. Chem. Phys. A 113, 13159-13166 (2009).