A global ab initio potential for HCN/HNC, exact vibrational energies, and comparison for experiment

✍ Scribed by Joseph A. Bentley; Joel M. Bowman; Bela Gazdy; Timothy J. Lee; Christopher E. Dateo

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 608 KB
• Volume: 198
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(92)85031-5

✦ Synopsis

An ab initio, i.e. from first principles, calculation of vibrational energies of HCN and HNC is reported. The vibrational calculations were done with a new potential derived from a tit to 1124 ab initio electronic energies, which were calculated using the highly accurate CCSD(T) coupled-cluster method in conjunction with a large atomic natural orbital basis set. The properties of this potential are presented, and the vibrational calculations are compared to experiment for 54 vibrational transitions, 39 of which are for zero total angular momentum, J=O, and 15 of whtch are for d= I. The level of agreement with experiment is unprecedented for a triatomic with two non-hydrogen atoms, and demonstrates the capability ofthe latest computational methods to give reliable predictions on a strongly bound triatomic molecule at very high levels of vibrational excitation.