Molecular structure and ring tunneling of phenyl formate as observed by microwave spectroscopy and quantum chemistry

Lynn Ferres (1) , Halima Mouhib (1, 2) , Wolfgang Stahl (1) , Martin Schwell (3) , Ha Vinh Lam Nguyen (3)

1 RWTH - Rheinisch-Westfälische Technische Hochschule Aachen University
2 MSME - Laboratoire de Modélisation et Simulation Multi Echelle
3 LISA (UMR_7583) - Laboratoire Interuniversitaire des Systèmes Atmosphériques

Phenyl formate has been investigated by molecular jet Fourier-transform microwave spectroscopy in the frequency range from 2 to 26.5 GHz. Quantum chemical calculations at the MP2/6-311++G(d,p) level of theory indicate that this molecule does not have a plane of symmetry at equilibrium, and that the phenyl ring performs a large amplitude tunneling motion from one side of the Cs configuration to the other. The tilt angle of the ring out of the H-(C=O)O plane is ±70° and the calculated tunneling barrier is only 28 cm–1. The two lowest torsional states vt = 0 and 1 are assigned in the experimental spectrum and fitted using the program SPFIT/SPCAT. The Coriolis splitting ΔE between these states is 46.2231(25) GHz, very close to the value of 48.24 GHz calculated using a simple two-top torsional Hamiltonian of the formate group and the phenyl ring.

Mots clés: rotational spectroscopy; phenyl ring tunneling; double minima potential

Domaines: Chimie théorique et/ou physique

Lynn Ferres, Halima Mouhib, Wolfgang Stahl, Martin Schwell, Ha Vinh Lam Nguyen. Molecular structure and ring tunneling of phenyl formate as observed by microwave spectroscopy and quantum chemistry. Journal of Molecular Spectroscopy, 2017, 337, pp.59-64. ⟨10.1016/j.jms.2017.04.017⟩. ⟨hal-03183099⟩