Photoionization spectroscopy of the SiH free radical in the vacuum-ultraviolet range
Abstract
The first measurement of the photoelectron spectrum of the silylidyne free radical, SiH, is reported between 7and 10.5 eV. Two main photoionizing transitions involving the neutral ground state, X + 1 Σ + ← X 2 Π, and a + 3 Π← X 2 Π, are assigned using ab initio calculations. The corresponding adiabatic ionization energies are derived,IE ad (X + 1 Σ + ) = 7.934(5) eV and IE ad (a + 3 Π) = 10.205(5) eV, in good agreement with our calculated values andthe previous determination by Berkowitz et al. [Berkowitz et al., J. Chem. Phys., 1987, 86, 1235] from a photoion-ization mass spectrometric study. The photoion yield of SiH recorded in this work exhibits a dense autoionizationlandscape similar to that observed in the case of the CH free radical [Gans et al. J. Chem. Phys., 2016, 144, 204307
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