A PHOTOELECTRON SPECTROSCOPIC STUDY OF SMALL SILICON-OXIDE CLUSTERS -SIO2, SI2O3, AND SI2O4

We present an anion photoelectron spectroscopic study of SiO2, Si2O3, and Si2O4. We obtained the photoelectron spectra of these small silico n oxide anion clusters at 4.66 eV photon energy. All the spectra show broad photodetachment features, suggesting that there is considerable geometry change between the anion and the neutral. The vertical detach ment energies are determined to be 2.76 (0.10), 2.75 (0.10), and 3.63 (0.1) eV for SiO2-, Si2O3-, and Si2O4-, respectively. The spectrum of Si2O3- shows a weak feature at lower binding energy, suggesting existe nce of another isomer. The spectra of GeO2- and Ge2O3- are also obtain ed and are compared to the silicon analogs. They are similar to the si licon oxide species, but both have higher detachment energies, 2.93 (0 .07) eV for GeO2- and 3.01 (0.07) eV for Ge2O3-. The Ge2O3- spectrum i s consistent with only one isomer. The structure and bonding of these small oxide clusters are discussed.