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

Poster session, D22 69Can Anyone Detect Phosphine's Splitting?Clara Sousa-Silva *,1 , Oleg Polyansky 1 , Sergei N. Yurchenko 1 , Jonathan Tennyson 1* clara.silva.10@ucl.ac.ukSousa-Silva C.Polyansky O.Yurchenko S.N.Tennyson J.1UCL, Department of Physics & Astronomy, Gower St, London WC1E 6BT, UKSplitting due to tunnelling via the potential energy barrier has played a significant role in thestudy of molecular spectra since the early days of spectroscopy. The observation of theammonia doublet led to attempts to find a phosphine analogous, but these have so far failed 1due to its considerably higher barrier (12300 cm -1 ) 2 . As part of the ExoMol 3 project anaccurate and comprehensive spectrum of phosphine has been simulated, for the first timedealing with levels in the range of the barrier height. The computational approach TROVE 4responsible for the creation of the spectrum has allowed an analysis of the tunnellingcharacteristics of phosphine, the results of which will be presented at the conference. Theseinclude the value of splitting in various vibrational states, the intensity of the inversionrotation,inversion-rovibrational lines and an assessment of the potential for observing thedoublets.The final room temperature line list of phosphine consists of approximately 137 million lines,and it will form a basis for a high temperature equivalent in the near future. Phosphine's rovibrationalenergies were computed using a new ‘spectroscopic' potential energy surface. Thiswas generated through a refinement of the ab initio [CCSD(T)/aug-cc-pV(Q+d)Z] 5 potentialenergy surface by fitting to the experimental ro-vibrational energies available in the literaturewith J = 0, 1, 2, 4, 10. An ab initio electric dipole moment [CCSD(T)/aug-cc-pVTZ] 6 wasused to obtain the Einstein coefficients. The results of this simulation are compared to theHITRAN 08 7 database and further literature.References[1] S. Belov, A. Burenin and O. Polyansky – J. M. Spectrosc., 90, 579 (1981).[2] P. Schwerdtfeger, L. J. Laakkonen and P. Pyykko – J. Chem. Phys, 96, 9 (1992).[3] J. Tennyson and S. N. Yurchenko – MNRAS, in press, arXiv:1204.0124 (2012).[4] S. N. Yurchenko, W. Thiel, and P .Jensen - J. Mol. Spectrosc., 245, 126 (2007).[5] R. I. Ovsyannikov, W. Thiel, S. N. Yurchenko, M. Carvajal, and P.Jensen - J. Chem.Physics., 129, 044309(2008).[6] S. N. Yurchenko, M. Carvajal, W. Thiel, and P. Jensen – J. Mol. Spectrosc., 239, 71(2006).[7] L. S. Rothman, I. E. Gordon, A. Barbe et al. - J. Quan. Spectrosc. & Rad. Transfer, 110,533-572 (2009).