Accounting for intra-molecular vibrational modes in open quantum system description of molecular systems
Abstract
Electronic-vibrational dynamics in molecular systems that interact with an environment involve a large number of degrees of freedom and are therefore often described by means of open quantum system approaches. A popular approach is to include only the electronic degrees of freedom into the system part and to couple these to a non-Markovian bath of harmonic vibrational modes that is characterized by a spectral density. Since this bath represents both intra-molecular and external vibrations, it is important to understand how to construct a spectral density that accounts for intra-molecular vibrational modes that couple further to other modes. Here, we address this problem by explicitly incorporating an intra-molecular vibrational mode together with the electronic degrees of freedom into the system part and using the Fano theory for a resonance coupled to a continuum to derive an “effective” bath spectral density, which describes the contribution of intra-molecular modes. We compare this effective model for the intra-molecular mode with the method of pseudomodes, a widely used approach in simulation of non-Markovian dynamics. We clarify the difference between these two approaches and demonstrate that the respective resulting dynamics and optical spectra can be very different.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 26, 2012
- Source ID
- 10.1063/1.4765329
Entities
People
- Alexander Eisfeld
- Jan Roden
- K. Birgitta Whaley
- Walter T Strunz
Organizations
- Defense Advanced Research Projects Agency
- German Research Foundation
- Harvard University
- Technische Universität Dresden
- University of California