Ab initio dipole moment and theoretical rovibrational intensities in the electronic ground state of PH3

作者：Yurchenko Sergei N; Carvajal Miguel; Thiel Walter; Jensen Per^*

来源：Journal of Molecular Spectroscopy, 2006, 239(1): 71-87.

DOI：10.1016/j.jms.2006.06.001

• phosphine
• PH3
• ab initio dipole moment surfaces
• rovibrational intensities
• energy clusters

We report a six-dimensional CCSD(T)/aug-cc-pVTZ dipole moment surface for the electronic ground state of PH3 computed ab initio on a large grid of 10080 molecular geometries. Parameterized, analytical functions are fitted through the ab initio data, and the resulting dipole moment functions are used, together with a potential energy function determined by refining an existing ab initio surface in fittings to experimental wavenumber data, for simulating absorption spectra of the first three polyads of PH3, i-e-, (v(2), v(4)), (v(1), v(3),2v(2), 2v(4), v(2) + v(4)), and (v(1) + v(2), v(3) + v(2), v(1) + v(4), v(3) + v(4), 2v(2) + v(4), v(2) + 2v(4), 3v(2), 3v(4)). The resulting theoretical transition moments show excellent agreement with experiment. A line-by-line comparison of the simulated intensities of the v(2)/v(4) band system with 955 experimental intensity values reported by Brown et a]. [L.R. Brown, R.L. Sams, I. Kleiner, C. Cottaz, L. Sagui, J. Mol. Spectrosc. 215 (2002) 178-203] gives an average absolute percentage deviation of 8.7% (and a root-mean-square deviation of 0.94 cm(-1) for the transition wavenumbers). This is very remarkable since the calculations rely entirely on ab initio dipole moment surfaces and do not involve any adjustment of these surfaces to reproduce the experimental intensities. Finally, we predict the line strengths for transitions between so-called cluster levels (near-degenerate levels formed at high rotational excitation) for J up to 60.

• 出版日期2006-9