A full-dimensional semiclassical calculation of vibrational mode selectivity in the tunneling splitting in a planar model of malonaldehyde

✍ Scribed by Yin Guo; Thomas D. Sewell; Donald L. Thompson

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 501 KB
• Volume: 224
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)00587-7

✦ Synopsis

A semiclassical method is used to treat proton tunneling in a planar model of malonaldehyde. Classical trajectories were calculated on a realistic potential-energy surface and WKB tunneling probabilities were calculated at turning points on the barrier separating the two equivalent potential wells. The calculated ground-state splitting, 24.5 cm-', is in good agreement with the experimental value of 2 1.6 cm-'. Vibrational mode selectivity was studied by calculating the splitting for all 15 modes for 2 kcal/mol excitation energy (35 kcal/mol total energy). The results show significant mode specific effects for all except some C-H stretching modes. This study demonstrates that multidimensional semiclassical tunneling can be readily and accurately treated.