Controlling the Excited-State Dynamics of Nuclear Spin Isomers Using the Dynamic Stark Effect

Abstract

Stark control of chemical reactions uses intense laser pulses to distort the potential energy surfaces of a molecule, thus opening new chemical pathways. We use the concept of Stark shifts to convert a local minimum into a local maximum of the potential energy surface, triggering constructive and destructive wave-packet interferences, which then induce different dynamics on nuclear spin isomers in the electronically excited state of a quinodimethane derivative. Model quantum-dynamical simulations on reduced dimensionality using optimized ultrashort laser pulses demonstrate a difference of the excited-state dynamics of two sets of nuclear spin isomers, which ultimately can be used to discriminate between these isomers.

Do we need delocalised wavefunctions for the excited state dynamics of 1,1-difluoroethylene?

“…[23][24][25][26][27][28][29][30][31] Using reduced dimensionality models, an association between the nuclear spin and an intermolecular torsion has been made 23,24,27,[32][33][34][35] and interference of torsional wavepackets within these reduced models leads to different excited state dynamics that can be associated to one or the other NSI, allowing their differentiation. 25,26,36 Even though the connection between NSIs and rotational levels has been extensively reported, the relation to torsional superpositions (as part of the vibrational wavefunction) has been mostly studied from the theoretical point of view. In this work we will focus on torsional superpositions as initial conditions for the dynamics, without making further connections to NSIs.…”

Taming Disulfide Bonds with Laser Fields. Nonadiabatic Surface-Hopping Simulations in a Ruthenium Complex

“…The observed excited state dynamics can be altered using additional pulses tailored to yield outcomes differing from those of the unperturbed dynamics. − Here, a classification into weak- and strong-field effects is useful, where weak-field pulses induce transitions between states but do not change the shape of the respective PESs and strong-field pulses influence the dynamics by introducing time-dependent PESs. The large number of successful simulations reported in the literature (see, e.g., refs − ) highlights their versatility. In general, two main avenues can be distinguished to design computationally control pulses .…”