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arXiv · 1912.06363

Modeling Non-Reversible Molecular Internal Conversion Using the Time-dependent Variational Approach with sD2 Ansatz

Mantas Jakučionis·Tomas Mancal·Darius Abramavičius
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Abstract

Effects of non-linear coupling between the system and the bath vibrational modes on the system internal conversion dynamics are investigated using the Dirac-Frenkel variational approach with the defined sD2 ansatz. It explicitly accounts for the entangled system electron-vibrational wavepacket states, while the bath quantum harmonic oscillator (QHO) states are expanded in a superposition of coherent states (CS). Using a non-adiabatically coupled three-level model, we show that quadratic system-bath coupling induces non-reversible internal conversion when the bath QHO wavepacket representation is highly non-Gaussian. The quadratic coupling results in a broadened and asymmetrically squeezed bath QHO wavepackets in the coordinate-momentum phase space. Additionally, we found that computational effort can be reduced using degenerate CSs to represent the initial bath wavepackets.

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Mantas Jakučionis, Tomas Mancal, Darius Abramavičius. 2019-12-13. Modeling Non-Reversible Molecular Internal Conversion Using the Time-dependent Variational Approach with sD2 Ansatz. https://doi.org/10.1039/d0cp01092h

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