Ultrafast photochemistry and electron-diffraction spectra in n->(3s) Rydberg excited cyclobutanone resolved at the multireference perturbative level

TL;DR

This study investigates the ultrafast photochemical dynamics of cyclobutanone in its Rydberg excited state using advanced simulations, revealing relaxation pathways, timescales, and resulting photoproducts, along with simulated electron-diffraction spectra.

Contribution

First application of multireference perturbative simulations to ultrafast Rydberg state dynamics of cyclobutanone, providing detailed relaxation pathways and spectroscopic predictions.

Findings

Relaxation to ground state occurs in approximately 822 fs.

Minimal involvement of triplet states during relaxation.

Simulated electron-diffraction spectra track excited state relaxation and product formation.

Abstract

We study the ultrafast time evolution of cyclobutanone excited to singlet n-->Rydberg state through XMS-CASPT2 nonadiabatic surface-hopping simulations. These dynamics predict relaxation to ground-state with a timescale of 822 +/- 45 fs with minimal involvement of triplets. The major relaxation path to the ground-state involves a three-state degeneracy region and leads to variety of fragmented photoproducts. We simulate the resulting time-resolved electron-diffraction spectra which track the relaxation of the excited state and the formation of various photoproducts in the ground-state.