1. Anharmonic rovibrational calculations of singlet cyclic C4 using a new ab initio potential and a quartic force field.
- Author
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Wang, Xiaohong, Huang, Xinchuan, Bowman, Joel M., and Lee, Timothy J.
- Subjects
PHYSICS research ,PERMUTATIONS ,QUANTUM chemistry ,POTENTIAL energy surfaces ,MOLECULAR force constants ,QUANTUM perturbations ,ISOTOPOLOGUES ,QUARTIC fields - Abstract
We report a CCSD(T)/cc-pCV5Z quartic force field (QFF) and a semi-global CCSD(T)-F12b/aug-cc-pVTZ potential energy surface (PES) for singlet, cyclic C4. Vibrational fundamentals, combinations, and overtones are obtained using vibrational second-order perturbation theory (VPT2) and the vibrational configuration-interaction (VCI) approach. Agreement is within 10 cm-1 between the VCI calculated fundamentals on the QFF and PES using the MULTIMODE (MM) program, and VPT2 and VCI results agree for the fundamentals. The agreement between VPT2-QFF and MM-QFF results is also good for the C4 combinations and overtones. The J = 1 and J = 2 rovibrational energies are reported from both VCI (MM) on the PES and VPT2 on the QFF calculations. The spectroscopic constants of 12C4 and two C2v-symmetry, single 13C-substituted isotopologues are presented, which may help identification of cyclic C4 in future experimental analyses or astronomical observations. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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