Renner-Teller intersections along the collinear axes of polyatomic molecules: H2CN as a case study.

摘要: The tetra-atomic C2H2+ cation is known to form Renner–Teller-type intersections along its collinear axis. Not too long ago, we studied the nonadiabatic coupling terms (NACTs) of this molecule [G. J. Halasz et al., Chem. Phys. 126, 154309 (2007)] and revealed two kinds intersections. (i) By employing one hydrogens as a test particle, fact that indeed corresponding (angular) NACTs produce topological (Berry) phases are equal 2π, which result anticipated in case Renner–Teller (ii) However, our big surprise, repeating study when atoms (in hydrogen) shifted from arrangement yields for phase value equals π (and not 2π). In other words, shifting (even slightly) causes intersection change character become Jahn–Teller intersection. This somewhat unexpected novel was later further analyzed ...