A refined quartic potential energy surface and large scale vibrational calculations for S0 thiophosgene

• We compute an ab initio quartic force field for S0 thiophosgene Cl2CS.
• We calculate vibrational energy levels using our specific variational method.
• We carry out an adjustment procedure on the ab initio computed quartic PES.
• We calculated a large number of excited vibrational level energies.
• We obtained a good fit between calculated and experimental frequencies.

In this work we present a full 6D quartic potential energy surface (PES) for S0 thiophosgene in curvilinear symmetrized bond-angle coordinates. The PES was refined starting from an ab initio field derived from acc-pVTZ basis set with CCSD(T) corrections for electron correlation. In the present calculations we used our variational method that was recently tested on formaldehyde and some of its isotopomers, along with additional improvements. The lower experimentally known vibrational levels for 35Cl2CS were reproduced quite well in the calculations, which can be regarded as a test for the feasibility of the obtained quartic PES.

Figure optionsDownload as PowerPoint slide