Intrinsic photophysics of nitrophenolate ions studied by cryogenic ion spectroscopy

The intrinsic photophysics of nitrophenolate isomers ( meta , para , and ortho ) was studied at low temperature using photodissociation mass spectrometry in a cryogenic ion trap instrument. Each isomer has distinct photophysics that affects the excited state lifetimes, as observed experimentally in their spectroscopic linewidths. Visible-light-induced excitation of m -nitrophenolate gives rise to well-resolved vibronic features in the spectrum of the S 1 state. The para and ortho isomers have broad spectra - even at cryogenic temperatures - due to their shorter excited state lifetimes and spectral congestion. We present computational evidence for mixing of the first and second excited states of o -nitrophenolate, leading to significant additional broadening in the experimental spectrum. The intrinsic photophysics of nitrophenolate isomers ( meta , para , and ortho ) was studied at low temperature using photodissociation mass spectrometry in a cryogenic ion trap instrument.