Vibrational spectra of vapor-phase 1,2-ethanedithiol and 2-mercaptoethanol were recorded to investigate weak intramolecular interactions. The spectra were recorded with conventional absorption spectroscopy and laser photoacoustic spectroscopy in the 2000-11,000 cm(-1) region. The room temperature spectra of each molecule are complicated by contributions from several conformers. Anharmonic oscillator local-mode calculations of the OH- and SH-stretching transitions have been performed to facilitate assignment of the different conformers in the spectra. We observe evidence of hydrogen-bond-like interactions from OH to S, but not from SH to O or S. The OH to S intramolecular interaction in 2-mercaptoethanol is weak and comparable to that found in the OH to O interaction in ethylene glycol.

Site-specific x-ray photoelectron spectroscopy together with density functional theory calculations based on the local density approximation have identified the chemical bonding, single-particle matrix element, and many-body effects in the x-ray photoelectron spectrum of corundum V 2 O 3 . Significant covalent bonding in both the upper and lower lobes of the photoelectron spectrum is found, despite the localized nature of the V 3d electrons that are responsible for the Mott behavior. We show that the approximate treatment of correlation dominates the discrepancy between theory and experiment in the near-Fermi-edge region and that many-body effects of the photoemission process can be modeled by Doniach-Šunjić ͓J. Phys. C 3, 285 ͑1970͔͒ asymmetric loss. Correlation effects govern the relative intensity and energy position of the higher level electron bands, and many-body effects dominate the "tail" region of both the upper and lower lobes of the photoemission spectrum.

Detection of phosphine (PH(3)) gas in the upper troposphere suggests that the biogeochemical P cycle also includes an atmospheric component that consists of volatile phosphorus-containing molecules. A reasonable end product for the oxidation of PH(3) in the atmosphere is phosphoric acid (H(3)PO(4)). We propose that H(3)PO(4) may be photodissociated into HOPO(2) and H(2)O in the stratosphere, where H(3)PO(4) is likely to be present in gaseous form. We have calculated the energy barrier of this reaction and show that in addition to electronic transitions, OH-stretching overtone transitions can also provide the necessary energy. OH-stretching fundamental and overtone transitions were calculated with the use of an anharmonic oscillator local mode model. The probability of overtone induced photodissociation was estimated with molecular dynamical reaction coordinate simulations. Electronic transitions were calculated with the equation of motion coupled cluster singles doubles method. We have calculated the photodissociation rate constants for absorption of visible, UV, and Lyman-alpha radiation at altitudes from 20 to 100 km. We show that at altitudes between 30 and 70 km, the photodissociation of H(3)PO(4) is likely to proceed via absorption in the UV region by electronic transitions.

We investigate the properties of Guggenite-α Cu 2 MgO 3 , which has an experimentally measured energy gap of approximately 1 eV. The band gap of Cu 2 MgO 3 , which is in the solar spectrum range makes it a potential candidate for photovoltaic applications. We calculate with PBE + U and LDA + U, and the SCAN functionals, the structure, formation energy and electronic structure of Cu 2 MgO 3 in its antiferromagnetic ground state and in the ferromagnetic phase. Finally we discuss the formation energy and band gap dependence on the U-J Hubbard potential and compare our results to experiment.