From a one-mode to a multi-mode understanding of conical intersection mediated ultrafast organic photochemical reactions

Abstract

This review discusses how ultrafast organic photochemical reactions are controlled by conical intersections, highlighting that decay to the ground-state at multiple points of the intersection space results in their multi-mode character.

Deciphering Methylation Effects on S2(ππ*) Internal Conversion in the Simplest Linear α,β-Unsaturated Carbonyl

“…However, it is important to note that the high excess kinetic energy upon reaching S 1 from S 2 leads to vigorous motion and hence a broader distribution of structures mediating population transfer. It should also be noted that the twist-pyramidalized MECIs of AC associated with charge-transfer character resemble those reported to mediate S 1 → S 0 decay in ethylene and butadiene. ,,,− Conversely, the lowest-energy S 1 /S 0 -MECI-N exhibits different covalent character (section S5) from that reported to facilitate S 1 → S 0 transfer via the covalent pathway in butadiene. ,,, Reference provides an instructive overview.…”

“…On the other hand, in MA, central methylation was proposed to retard the motion along the nonadiabatic coupling vector dominated by pyramidalization at the α C atom, leading to a less efficient and hence slower decay. Recently, the faster TRPES behavior of CR was reinterpreted in a multimode picture . Specifically, the efficient nonadiabatic transfer in CR was rationalized on the basis of a strong coupling (due to lack of symmetry at the conical intersection) between the torsion and β C atom pyramidalization modes at the intersection.…”

Smooth Things Come in Threes: A Diabatic Surrogate Model for Conical Intersection Optimization

“…They were once considered an academic curiosity, but they are nowadays known to be ubiquitous in molecular systems and with very significant conquences for their photophysical and photochemical behavior. CIs have been extensively studied and described before, − ,− and here only the most relevant aspects for the rest of the article will be given.…”

Smooth Things Come in Threes: A Diabatic Surrogate Model for Conical Intersection Optimization

“…They were once considered an academic curiosity, but are nowadays known to be ubiquitous in molecular systems and with very significant conquences for their photophysical and photochemical behavior. CIs have been extensively studied and described before, [7][8][9][10][11][37][38][39][40][41] and here only the most relevant aspects for the rest of the article will be given.…”