Abstract

PAZ, J.-L. et al. On the Optical Bloch Equations in Complex Systems with Intramolecular Coupling. Rev Politéc. (Quito) [online]. 2020, vol.46, n.2, pp.29-38. ISSN 2477-8990.  https://doi.org/10.33333/rp.vol46n2.03.

We propose modifications of the conventional optical Bloch equations for a complex system, when we consider intermolecular coupling effects. We model the isolated molecule as Born-Oppenheimer energy curves consisting of two-electronic states described as harmonic potentials, with minima displaced in nuclear coordinates and energy. We consider two-vibrational states and we include non-adiabatic effects for this two states model. Inclusion of a residual perturbation$\tilde{H}$, which may arise from a residual electron-electron correlation and/or spin-orbit coupling terms in the Hamiltonian of the system, may couple the above electronic states, causing the separation of the two curves according to the avoided-crossing rule. The extended equations of optical Bloch allow to establish the dynamics of a molecular system of adiabatic states subject to the interaction of a thermal reservoir and interacting with electromagnetic fields. The equations show that by making the intramolecular coupling factor zero, the conventional optical Bloch equations are recovered for a molecular system with harmonic potentials whose minima are found in exactly the same nuclear coordinate subject to the Born-Oppenheimer approximation.

Keywords : intramolecular coupling; optical Bloch equations; non-adiabatic effects; Born-Oppenheimer.

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