Photophysics of Protonated and Microhydrated 2-Aminobenzaldehyde: Theoretical Insights into Photoswitchability of Protonated Systems.

The photoswitchability of a protonated aromatic compound (2-aminobenzaldehyde, 2ABZH+) in its individual and microhydrated states has been addressed based on the RI-MP2/RI-CC2 theoretical methods. Our calculated results give insight into the ultrafast nonradiative deactivation mechanism of the 2ABZH+, driven by a conical intersection between the S1/ S0 potential energy surfaces. Also, it has been predicted that protonation accompanies a significant blue shift effect on the first 1ππ* excited state of 2ABZ by 0.87 eV (at least 50 nm).