Structural and energy properties of interstitial molecular hydrogen in single-crystal silicon

The structural and energy characteristics of interstitial molecular hydrogen in single-crystal silicon are theoretically studied. The dependence of the potential energy of the system on the position and orientation of the interstitial defect is investigated, and the mechanism of interaction of a hydrogen molecule with a silicon crystal is considered. A three-dimensional model is employed to calculate the energy spectrum of H2 in Si, and the obtained dispersion law is analyzed

Radiative cooling of H3O+ and its deuterated isotopologues

In conjunction with ab initio potential energy and dipole moment surfaces for the electronic ground state, we have made a theoretical study of the radiative lifetimes for the hydronium ion H$_3$O$^{+}$ and its deuterated isotopologues. We compute the ro-vibrational energy levels and their associated wavefunctions together with Einstein coefficients for the electric dipole transitions. A detailed analysis of the stability of the ro-vibrational states have been carried out and the longest-living states of the hydronium ions have been identified. We report estimated radiative lifetimes and cooling functions for temperatures $<$ 200 K. A number of long-living meta-stable states are identified, capable of population trapping.Comment: Phys. Chem. Chem. Phys., 201

SO4 in Cadmium Chalcogenides

A study combining infrared (IR) absorption spectroscopy and first-principles theory is presented for a sulfur–oxygen complex in CdSe characterized by IR absorption lines located at 1094, 1107, and 1126 cm-1 (10 K). The properties of the center are compared to a similar species occurring in CdTe that gives rise to two absorption lines at 1097 and 1108 cm-1 (10 K). Temperature- and polarization-sensitive measurements performed on 18O-enriched samples reveal that for both materials the IR absorption lines are due to split ν3 stretch vibrations of a distorted sulfate (SO4) tetrahedron, whereby the local point group of the SO4 complex is reduced to Cs and C3v in hexagonal CdSe and cubic CdTe, respectively. Measurements on the vibrational spectrum of the sulfate species in the spectral range of symmetric stretch (ν1), bend (ν4), and combinationmodes (ν1 þ ν3) are presented. The cation vacancy VCd is discussed as a likely site occupied by SO4 in CdSe

Structural and energy properties of interstitial molecular hydrogen in single-crystal silicon

The structural and energy characteristics of interstitial molecular hydrogen in single-crystal silicon are theoretically studied. The dependence of the potential energy of the system on the position and orientation of the interstitial defect is investigated, and the mechanism of interaction of a hydrogen molecule with a silicon crystal is considered. A three-dimensional model is employed to calculate the energy spectrum of H2 in Si, and the obtained dispersion law is analyzed

SO4* complex in CdTe: Infrared absorption spectroscopy and first-principles calculations

A sulfur-oxygen complex in CdTe characterized by IR absorption lines at 1097 and 1108 cm−1 is studied by means of infrared absorption spectroscopy and first principles theory. Temperature-sensitive measurements performed on samples with different 16O: 18O isotope ratios show that these lines are due to a split ν3 stretch vibrational mode of a disturbed sulfate ion (SO2−4 ) transformed under the A1 (1097 cm−1) and E (1108 cm−1) representations of the C3v point group. The ν1 symmetric stretch, ν4 bend, and ν1 + ν3 combination modes of the ion are also identified. An axially disturbed SO4 located at the Cd vacancy site is proposed as a microscopic model of the complex

SO4 in cadmium chalcogenides: CdSe versus CdTe

A study combining infrared (IR) absorption spectroscopy and first-principles theory is presented for a sulfur-oxygen complex in CdSe characterized by IR absorption lines located at 1094, 1107, and 1126 cm(-1) (10 K). The properties of the center are compared to a similar species occurring in CdTe that gives rise to two absorption lines at 1097 and 1108 cm(-1) (10 K). Temperature- and polarization-sensitive measurements performed on O-18-enriched samples reveal that for both materials the IR absorption lines are due to split nu 3 stretch vibrations of a distorted sulfate (SO4) tetrahedron, whereby the local point group of the SO4 complex is reduced to Cs and C3v in hexagonal CdSe and cubic CdTe, respectively. Measurements on the vibrational spectrum of the sulfate species in the spectral range of symmetric stretch (nu 1), bend (nu 4), and combination modes (nu 1+nu 3) are presented. The cation vacancy VCd is discussed as a likely site occupied by SO4 in CdSe