Torsions of N-methylpyrrole and its cation

Abstract

Torsional levels in N-methylpyrrole are investigated in the ground (S0) and first excited (S1) neutral states using two-dimensional laser-induced fluorescence (2D-LIF), and in the ground state cation (D0+) using zero-electron-kinetic-energy (ZEKE) spectroscopy. The ZEKE spectra confirm the largely Rydberg nature of the S1 state. The activity seen in both the 2D-LIF and ZEKE spectra are indicative of vibronic (including torsional) interactions and torsional potentials in the three electronic states are deduced, and are consistent with calculated geometries. The adiabatic ionization energy of N-methylpyrrole is derived as 64250 ± 5 cm−1.