Mass-Analyzed Threshold Ionization Study of Vinyl Chloride Cation in the First Excited Electronic State Using Vacuum Ultraviolet Radiation in the 107−102.8 nm Range

Abstract

Vibrational spectrum of vinyl chloride cation in the first excited electronic state, A2 A', was obtained by one-photon mass-analyzed threshold ionization (MATI) spectroscopy. Use of an improved vacuum ultraviolet radiation source based on four-wave sum frequency mixing in Hg resulted in excellent sensitivity for the MATI signals. From the MATI spectrum, the ionization energy to the A2 A' state of the cation was determined to be 11.6667 +/- 0.0006 eV. Nearly complete vibrational assignment for the MATI peaks was possible by utilizing the vibrational frequencies and Franck-Condon factors calculated at the DFT and TDDFT/B3LYP levels with the 6-311++G(3df,3pd) basis set. Geometry of the cation in the A2 A' state was determined by Franck-Condon fitting of the MATI spectrum.

Low-Lying Electronic States and Cl-Loss Photodissociation of the C2H3Cl+ Ion Studied Using Multiconfiguration Second-Order Perturbation Theory

“…Using the reported experimental AIE values for value for the 1 2 A′ state is evaluated to be 1.72 eV. The experimental geometry of the A state of C 2 H 3 Cl + was reported by Kim et al, 4 and we found no reported experimental geometries for the other three states in the literature. Photodissociation studies for the C 2 H 3 Cl + ion were carried out by several groups, 5,[11][12][13]17,18 and the observed products and the measured dissociation energies and appearance energies were reported.…”

“…Experimental vertical ionization energies (VIEs) for the four states of C 2 H 3 Cl + were already reported by many groups. [3][4][6][7][8][9][10][11][12][13][14][15][16] On the basis of the experimental VIE values for different states of the ion, relative energy values (denoted by T v ′ in the present paper) of the excited states to the ground state of the ion at the ground-state geometry of the neutral molecule can be evaluated. Using the experimental VIE values for the X, A, B, and C states (10.18, 11.72, 13.14, and 13.56 eV, respectively) reported by Lake and Thompson, 6 the T v ′ values for the 1 2 A′, 2 2 A′′, and 2 2 A′ states are evaluated to be 1.54, 2.96, and 3.38 eV, respectively.…”

Multireference Configuration Interaction Study of the Vibronic Transitions and Photodissociation of Vinyl Bromide and Vinyl Chloride Radical Cations in the Second Excited State

“…Although multiphoton excitation by pulsed lasers via an intermediate excited state is currently the most typical method to generate molecules in Rydberg states, one-photon ionization with vacuum ultraviolet (VUV) radiation is advantageous as the intensities of vibronic bands can be compared with Franck−Condon factors (FCFs) between the neutral ground state and the ionized state . Recently Kim et al developed VUV radiation sources of up to 12 eV by four-wave mixing of Hg, which was successfully applied to generate not only the ground but also the first excited ionized state of vinyl halides. , Vibronic bands in MATI spectra of the ground and first excited states of radical cations were successfully analyzed using calculated FCFs.…”

Cl-Loss Dynamics of Vinyl Chloride Cations in the B2A″ State: Role of the C2A′ State

“…A series of sharp peaks is observed in the energy range of 11.6−12.1 eV, which are assigned to the vibrational bands of the A 2 A′ state based on previously reported conclusions. 9,11 The peak with a maximum intensity at 11.670 eV is assigned to the origin band of the A 2 A′ state. The v 6 (C−H−H rock), v 8 (C−Cl stretching), and v 9 (C−C−Cl bend) vibrational modes are also populated.…”

“…The adiabatic ionization energy of C 2 H 3 Cl was determined to be 10.0062 ± 0.0003 eV using high-resolution zero-kinetic-energy (ZEKE) PES . The ionization energy of the A 2 A′ and B 2 A″ states was measured using mass-analyzed threshold ionization (MATI) and MATI photodissociation yield (PDY) spectroscopy . In the MATI-PDY spectrum, several vibrational peaks were observed in the lower-energy region of the B 2 A″ state, implying that the ionic state has a shallow potential well …”