Probing the conical intersection dynamics of the rna base uracil by UV-pump stimulated-Raman-probe signals; ab initio simulations
BP Fingerhut, KE Dorfman… - Journal of chemical theory …, 2014 - ACS Publications
Journal of chemical theory and computation, 2014•ACS Publications
Nonadiabatic electron and nuclear dynamics of photoexcited molecules involving conical
intersections is of fundamental importance in many reactions such as the self-protection
mechanism of DNA and RNA bases against UV irradiation. Nonlinear vibrational
spectroscopy can provide an ultrafast sensitive probe for these processes. We employ a
simulation protocol that combines nonadiabatic on-the-fly molecular dynamics with a mode-
tracking algorithm for the simulation of femtosecond stimulated Raman spectroscopy (SRS) …
intersections is of fundamental importance in many reactions such as the self-protection
mechanism of DNA and RNA bases against UV irradiation. Nonlinear vibrational
spectroscopy can provide an ultrafast sensitive probe for these processes. We employ a
simulation protocol that combines nonadiabatic on-the-fly molecular dynamics with a mode-
tracking algorithm for the simulation of femtosecond stimulated Raman spectroscopy (SRS) …
Nonadiabatic electron and nuclear dynamics of photoexcited molecules involving conical intersections is of fundamental importance in many reactions such as the self-protection mechanism of DNA and RNA bases against UV irradiation. Nonlinear vibrational spectroscopy can provide an ultrafast sensitive probe for these processes. We employ a simulation protocol that combines nonadiabatic on-the-fly molecular dynamics with a mode-tracking algorithm for the simulation of femtosecond stimulated Raman spectroscopy (SRS) signals of the high frequency C–H- and N–H-stretch vibrations of the photoexcited RNA base uracil. The simulations rely on a microscopically derived expression that takes into account the path integral of the excited state evolution and the pulse shapes. Analysis of the joint time/frequency resolution of the technique reveals a matter chirp contribution that limits the inherent temporal resolution. Characteristic signatures of relaxation dynamics mediated in the vicinity of conical intersection are predicted. The C–H and N–H spectator modes provide high sensitivity to their local environment and act as local probes with submolecular and high temporal resolution.
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