Structural Isomers of Ti₂O₄ and Zr₂O₄ Anions Identified by Slow Photoelectron Velocity-Map Imaging Spectroscopy

Abstract

High-resolution anion photoelectron spectra are reported for the group 4 metal dioxide clusters Ti2O4(-) and Zr2O4(-). Slow photoelectron velocity-map imaging (SEVI) spectroscopy of cryogenically cooled, mass-selected anions yields photoelectron spectra with submillielectronvolt resolution, revealing extensive and well-resolved vibrational progressions. By comparison of the spectra with Franck-Condon simulations, we have identified the C(2v) and C(3v) isomers as the ground states of Ti2O4(-) and Zr2O4(-) anions, respectively. Minor contributions from the C(2h) isomer of Ti2O4(-) and the C(2v) isomer of Zr2O4(-) are also seen. The SEVI spectra yield upper bounds for the adiabatic detachment energies, as well as vibrational frequencies for various modes of the neutral Ti2O4 and Zr2O4 species.

Dissociative Water Adsorption on Gas-Phase Titanium Dioxide Cluster Anions Probed with Infrared Photodissociation Spectroscopy

“…1. An IRPD spectrum could not be acquired for D 2 -tagged (TiO 2 ) 2 − , as it is known to react with molecular hydrogen rather than form a physisorbed complex [46,77]. The global minimum-energy structures for the bare clusters identified in previous work [13,46,78] are reproduced in Fig.…”

“…The global minimum-energy structure of bare (TiO 2 ) 2 − , 2-0-a (Fig. 2), has C 2v symmetry with the unpaired electron delocalized over both Ti atoms [46,78]. Upon dissociative adsorption of one D 2 O on 2-0-a, two low energy structures of C 1 symmetry, 2-1-a and 2-1-b (Fig.…”

“…While there is a growing body of work on the gas-phase spectroscopy of bare titanium dioxide clusters [13,[42][43][44][45][46], studies probing their interactions with water are more sparse. Early work from the Castleman group reported on the mass spectrum of the water-solvated TiO + cation [47].…”

Isomer-specific vibronic structure of the 9-, 1-, and 2-anthracenyl radicals via slow photoelectron velocity-map imaging

“…The cryo-SEVI technique used here is a high-resolution variant of PES and yields spectra of complex anions with sub-meV resolution (17,35,36). Specific anthracenyl anion isomers are prepared using trimethylsilyl-anthracene precursors and cooled to cryogenic temperatures (∼10 K) before photodetachment, eliminating hot spectral features and narrowing the rotational profiles of the observed peaks.…”

Electronic structure of the diatomic VO anion: A combined photoelectron-imaging spectroscopic and theoretical investigation

“…Due to their significant roles in catalysis, surface chemistry, and magnetic materials, transition metal (TM) oxides have been subject to numerous recent experimental and theoretical investigations [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Vanadium oxides, in particular, are the most versatile metal oxide catalysts predominantly used in industrial catalytic processes [17,18], making the understanding of the nature of vanadium-oxygen bonds highly valuable.…”