Experimental and theoretical study of valence electron structure of cyclopentane: Electron momentum spectroscopy and molecular dynamics sampling

We report a combined experimental and theoretical study on the valence electron structure of cyclopentane. The binding energy spectrum and electron momentum profiles were measured using a high-sensitivity (e, 2e) apparatus in symmetric non-coplanar kinematic arrangement at an incident energy of 1200 eV plus binding energy. To account for the vibrational effect, the experimental results were compared with the theoretical calculations based on the thermal sampling molecular dynamics (TSMD) method. The results show the significant influence of nuclear dynamics, including ring-puckering and pseudorotation, on the electron momentum profiles. The TSMD method, which incorporates all vibrational modes and full $Q$-space sampling, provides the best agreement with experiment, revealing the critical role of molecular vibrations in shaping the electronic structure of cyclopentane.