Vibronic contribution to static molecular hyperpolarizabilities

✍ Scribed by G.P. Das; A.T. Yeates; D. Dudis

• Book ID: 103031703
• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 539 KB
• Volume: 212
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)85503-g

✦ Synopsis

A simplified semiempirical scheme (AMl) is developed as a handy tool to calculate vibrational corrections to hyperpolarizabilities of moderately large planar conjugated systems. In formulating the scheme Born-Oppenheimer (BO) approximation is assumed and only those normal modes are considered which correspond to vibration along the direction of the field. Ab initio calculations are performed to calibrate and justify the various steps involved in the scheme. Using this approach vibronic corrections to the third-order polarizabilities y are computed for a number of systems including the polyenes C2,Hz.+z, n=3,4 and 5. The corrections are large and may explain some of the discrepancies that are found to exist between experiment and theory.