On the performance of gradient-corrected approximation functionals and polarizable continuum model in the study of 1,2,3-triazine in water

Time dependent density functional theory (TD-DFT) using different gradient-corrected density functionals, Becke's three-parameter hybrid method using the Lee-Yang-Parr correlation functional (B3LYP), Becke's exchange functional and Lee-Yang-Parr correlation functional (BLYP) and an hybrid DFT/HF approach based on the Perdew-Burke-Erzenrhof exchange-correlation functional (PBE1PBE), are applied to calculate vertical transitions from ground to the low-lying singlet electronic excited states of 1,2,3-triazine, in vacuum and in aqueous solution. Our results are in excellent agreement with a recent high resolution UV/VUV experimental work in the gas phase and with previous high level computational methods in vacuum and in solution. The results clearly show the potentialities of the combined TD-DFT/CPCM approach, within the gradient-corrected approximation (GGA), on aquo-complexes for the study of structural and spectroscopic properties in liquid phase.