VUV photoionization of the CH2NC radical adiabatic ionization energy and cationic vibrational mode wavenumber determinations

Bérenger Gans (1) , Sebastian Hartweg (2, 3) , Gustavo A Garcia (3) , Séverine Boyé-Péronne (1) , Oliver J Harper (1) , Jean-Claude Guillemin (4) , Jean-Christophe Loison (1)

1 ISMO - Institut des Sciences Moléculaires d'Orsay
2 ESRF - European Synchrotron Radiation Facility
3 SSOLEIL - Synchrotron SOLEIL
4 ISCR - Institut des Sciences Chimiques de Rennes

The photoelectron spectroscopy of CHNC (isocyanomethyl) radical species is investigated for the first time between 9.3 and 11.2 eV in the vicinity of the first photoionizing transition XA← X B. The experiment combines a microwave discharge flow-tube reactor to produce the radicals through the CHNC + F → CHNC + HF reaction, a VUV synchrotron radiation excitation, and a double imaging electron/ion coincidence spectrometer which allows the recording of mass-selected threshold photoelectron spectra. Assignment of the observed vibrational structure of the CHNC cation is guided by ab initio calculations and Franck-Condon simulations. From the experimental spectrum, the first adiabatic ionization energy of the CHNC radical is measured as 9.439(6) eV. Fundamental wavenumbers are determined for several vibrational modes of the cation: [small nu, Greek, tilde](CH symmetric stretch) = 2999(80) cm, [small nu, Greek, tilde](NC stretch) = 1925(40) cm, [small nu, Greek, tilde](HC-N stretch) = 1193(40) cm, [small nu, Greek, tilde](CNC out-of-plane bend) = 237(50) cm, and [small nu, Greek, tilde](CH rock) = 1185(60) cm.

Domaines: Chimie théorique et/ou physique

Bérenger Gans, Sebastian Hartweg, Gustavo A Garcia, Séverine Boyé-Péronne, Oliver J Harper, et al.. VUV photoionization of the CH2NC radical adiabatic ionization energy and cationic vibrational mode wavenumber determinations. Physical Chemistry Chemical Physics, 2020, 22 (22), pp.12496-12501. ⟨10.1039/d0cp01901a⟩. ⟨hal-02862237⟩