Non-Condon effect

First, as the molecule on which the chromophore sits rotates, this projection will change. Second, the magnitude of the transition dipole may depend on bath coordinates, which in analogy with gas-phase spectroscopy is called a non-Condon effect For water, as we will see, this latter dependence is very important [13, 14]. In principle there are off-diagonal terms in the Hamiltonian in this truncated two-state Hilbert space, which depend on the bath coordinates and which lead to vibrational energy relaxation [4]. In practice it is usually too difficult to treat both the spectral diffusion and vibrational relaxation problems at the same time, and so one usually adds the effects of this relaxation phenomenologically, and the lifetime 7j can either be calculated separately or determined from experiment. Within this approach the line shape can be written as [92 94]... 

In a recent experimental study involving the temperature dependences of the IR and Raman line shapes, Loparo et al. [14] confirmed that non-Condon effects are important in experimental (and theoretical ) line shapes, and they found a frequency dependence to the dipole derivative that is qualitatively similar to the form used in our work. 

The solvent sensitivity of the diabatic quantities (//DA and AfiDA) is an interesting manifestation of a solvent-driven non-Condon effect, in which the solute polarizability, responding to the RF as the solvent is varied, changes the effective two-state electronic space used to model the ET process [29],... 

Ishii, K., Takeuchi, S., Tahara, T., Pronounced Non Condon Effect as the Origin of the Quantum Beat Observed in the Time resolved Absorption Signal from Excited state cis Stilbene, J. Phys. Chem. A 2008, 112, 2219 2227. 

During the n/2 pulse a coherent population in J is prepared, associated with both the ground- and the excited-electronic-state vibrational wavepacket. Hence, a coherent ro-vibrational wavepacket is formed. In analogy with the case where non-Condon effects play a significant role in the vibrational portion of the wavefunction, the rotational wavepackets in general are not identical on the two surfaces. Nevertheless, the two rotational wavepackets should be sufficiently similar to be strongly coupled. 

Vg being the matrix element of this operator between the g) and i) diabatic electronic states Vgi may depend on the vibrational degrees of freedom due to non-Condon effects. 

Xie et al. [62] presented (transition) dipole moments for the X A /C B2 system of SO2 calculated at the MR-AQCC/ANO level of theory. The DMSs and TDMSs were used to simulate spectra in semi-quantitative agreement with available experimental data theoretical studies of the absorption spectrum of SO2 and the resonance emission spectra from vibrational levels in the C 52 electronic state below the predissociation threshold. A strong non-Condon effect is found for the emission spectra. The TDM surfaces were plotted and analysed but the analytical representation was not given. 

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