Albrecht s Theory

The dispersion phenomenon has been quantitatively approached by three models. Initially, Albrecht s theory (Tang and Albrecht, 1970) was applied to the finite segments of the polymer. Then, in the case of materials such as trans-Vk, use of an empirical distribution function P N) for the conjugation length made it possible to exactly reproduce the line shapes and line intensities resulting from excitation with different laser lines ... 

Recendy Okamoto [257] evaluated additional second-order terms to q. (8.68), thus expanding the applicability of Albrecht s theory. The emphasis is laid on the role of forbidden electronic transitions in generating resonance Raman intensities. It has been shown that (1) the Raman line can derive intensity from a forbidden electronic transition... 

An exact asymptotic value of p [X) is still unknown, but it is expected to be somewhere between 1.55 and 1.72, the upper limit being suggested by Stockmayer and Albrecht s perturbation theory of the friction constant [239). 

Melinger J S and Albrecht A C 1986 Theory of time- and frequency-resolved resonance secondary radiation from a three-level system J. Chem. Phys. 84 1247-58... 

Albrecht A C, Clark R J H, Oprescu D, Owens S J R and Svensen C 1994 Overtone resonance Raman scattering beyond the Condon approximation transform theory and vibronic properties J. Chem. Phys. 101 1890-903... 

Morell, J.A., Albrecht, A.C. Second-order hyperpolarizability of p-nitroaniline calculated from perturbation theory based expression using CNDO/S generated electronic states. Chem. Phys. Lett. 64, 46-50 (1979)... 

Equation (3) is the starting point on the resonance Raman effect approach, which has been developed by Albrecht and others [102,124]. In this theory the Bom-Oppenheimer approach is assumed, that is, the total wave function is considered as a product between an electronic and a vibrational function, for example, gi) = g) i). The dependence of the transition moment with the vibrational coordinates is included by a Taylor s expansion in the normal modes ... 

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