Development of real-time vibrational spectroscopy of molecules in electronic excited states: toward mapping molecular potential energy hypersurfaces

Abstract

We have developed an experimental system for real-time vibrational spectroscopy of molecules in a specific electronic excited state. A synchronized UV light source and a few-cycle visible laser pulse were utilized to prepare and investigate the ultrafast dynamics of molecules in the electronic excited states. A multichannel lock-in amplifier detection system operating in a tandem double lock-in detection mode was used to extract the signal correlated only to the UV and visible pump pulses. Real-time vibrational spectroscopy of chrysene in the triplet state and 1′, 3′-dihydro-1′, 3′, 3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2, 2′-(2H)-indole] in a photochromic state was demonstrated.