Internal rotation in the para-difluorobenzene–nitrogen van der Waals complex

Abstract

Barriers hindering internal rotation in the para-difluorobenzene–nitrogen complex have been obtained by fitting experimental transition frequencies from a rotationally resolved UV spectrum using a semirigid C_2v top–C_2v frame internal rotation model. In both electronic states, the barrier has been found to be very low, with upper limits of 20 and 6 cm⁻¹ for S₀ and S₁, respectively.