Quantum chemical investigation of spectral-luminescent properties of zwitterion and lactone forms of rhodamine B

Abstract

A quantum chemical software package based on a semiempirical INDO method with original spectroscopic parameterization is used to calculate the electronically excited states of lactone and zwitterion forms of rhodamine B. The rate constants of photophysical processes are estimated, and the fluorescence quantum yields are calculated. It is established that the wave function of the S 1 state in the zwitterion form is localized on the pyronin fragment and delocalized throughout the molecule in the lactone form.