Infrared and Raman spectra of MnS2

The infrared and Raman spectra of the pyrite-type crystal MnS₂ are reported. Nine of the ten optically allowed $\text{q≌0}$ phonons are observed. A comparison of the phonon frequencies with those of FeS₂ allows us to conclude that the electrostatic forces as well as the covalent sulfur-sulfur bonds are about the same strength in the two compounds. The short-range forces between metal and sulfur ions in the two cases, however, are quite different.     

Infrared and Raman spectra of GeSe2

Far infrared room temperature reflectivity spectra have been measured with polarized light for single crystal GeSe₂ in the range 40–400 cm^-1 for all three principal directions. Altogether 15 “Reststrahlen” peaks were observed, seven for E∥a, six for E∥b and only two for E∥c. Optical parameters were calculated using both Kramers-Krönig integration and a fitting procedure. A nonpolarized Raman spectrum of GeSe₂ was also measured. 17 Raman active lines were observed. The strongest one was at 213cm^-1.     

Infrared and Raman spectra of cyclo octasulphur oxide (S8O)

The infrared spectrum (200–4000 cm^?1) and the laser Raman spectrum (10–1400 cm^?1) of S₈O are reported. The observed bands are compared with those of S₈ and SOCl₂ and a tentative assignment is given in accordance with the molecular symmetry C₈.     

Infrared and laser Raman gas spectra of GeD4

The ν₂(e) and ν₃(f₂) Raman spectra and the 2ν₃ infrared spectrum of gaseous GeD₄ have been observed and analyzed. The new data have been combined with those of the ν₃(f₂) infrared band to derive an improved set of rovibrational constants. The analysis yields B₀ = 1.3544 ± 0.0010 cm^?1 and $\text{r}{}_0\text{= 1.5223 ± 0.0006}\text{A}\text{?}$.     

Infrared and laser Raman gas spectra of SnH4

In the present work the ν₃(f₂) Raman band and the 2ν₃ infrared band of SnH₄ are reported. Analyses have been performed for the ν₃(f₂) Raman band and the ν₂(e), ν₃(f₂), ν₄(f₂) and 2ν₃ infrared bands. The interatomic distance in the ground state has been found to be 1.7108 ± 0.0010 Å.     

Infrared and laser Raman gas spectra of SiH4 and SiD4

The ν₂(e) and ν₃(f₂) Raman spectra have been examined. For ²⁸SiH₄ the ν₂(e) and ν₄(f₂) infrared bands are partly analyzed and compared with a computed band-contour; the ν₁ + ν₃ combination infrared band has been presented. For ²⁸SiH₄ the 2ν₃ overtone infrared band has been observed and analyzed. The new data are combined with those of the ν₃(f₂) infrared bands to derive an improved set of rovibrational constants of ²⁸SiH₄ and ²⁸SiD₄. The analyses yield $\text{r}{}_0\text{= 1.4806 ± 0.0008}\text{A}\text{?}$ for ²⁸SiH₄ and $\text{r}{}_0\text{= 1.4784 ± 0.0006}\text{A}\text{?}$ for ²⁸SiD₄ in agreement with the Laurie-Herschbach theorem.     

Photoelectron and electronic absorption spectra of SCl2, S2Cl2, S2Br2 and (CH3)2S2

Photoelectron and electronic absorption spectra of SCl₂, S₂Cl₂, S₂Br₂, and (CH₃)₂S₂ have been measured and analyzed. Quantum chemical calculations (CNDO/ 2 and MWH (Mulliken-Wolfsberg-Helmholtz) have been carried out and the electronic structures have been described in terms of molecular orbital theory. The variation in differential photoionization cross-section as a function of incident photon energy and results of MO computations are used to identify ionization bands and assign ground state MO configurations. Suggested ground state electronic structures coupled with computed virtual MO's are used to interpret the visible and near-ultraviolet electronic absorption spectra. The low energy excited states are described as molecular states followed by the initial members of Rydberg series. Calculated oscillator strengths for molecular transitions are in good agreement with those observed experimentally. Quantum defects, δ, for the Rydberg states have been calculated from the Rydberg equation using the adiabatic first ionization potential.     

Effect of aggregation on the radiative (T1 → S0) and nonradiative (T1⇝S0 and S1⇝T1) transitions in xanthene dyes

The measurement of triplet decay time (τ_p) and the relative yields of phosphorescence to fluorescence (φ_p/φ_f) have been made in solutions of xanthene dyes. The value of φ_p/φ_f increases while that of τ_p decreases as the concentration of the solution is increased. The rate constants k_p, k_qp and k_is have been estimated. It is found that the values of k_qp and k_is increase while that of k_p remains substantially constant for the entire range of concentration. The deuterium solvent effect is observed in τ_p and φ_p.     

Raman scattering and optical absorption in S2N2 and partially polymerized S2N2 films

Raman scattering and optical absorption measurements between 0.5 and 5.0 eV on crystalline films of S₂N₂ and partly polymerized S₂N₂ have been made for the first time. The Raman active molecular and librational phonons have been observed and assigned. The Raman spectra of partly polymerized S₂N₂ show the appearance of weak scattering at 635 cm⁻¹ and appreciable broadening of the librational phonon peaks. Optical absorption maxima occur at 4.0 and 4.7 eV in pure S₂N₂ at 14 K, while absorptions at 0.86, 1.1 and 4 eV evolve with increasing polymerization.     

Electronic structure and the infrared absorption and Raman spectra of the semiconductor clusters C24, B12N12, Si12C12, Zn12O12, and Ga12N12

The optimized configurations, electronic structures, charge transfers, band gaps, total energies, cohesive energies, electron density maps, infrared absorption spectra, Raman spectra, and relevant modes of natural acoustic vibrations for the semiconductor clusters C₂₄, B₁₂N₁₂, Si₁₂C₁₂, Zn₁₂O₁₂, and Ga₁₂N₁₂ are calculated using the ab initio Hartree-Fock method in the 6–31G basis set. Original Russian Text ? V.V. Pokropivny, L.I. Ovsyannikova, 2007, published in Fizika Tverdogo Tela, 2007, Vol. 49, No. 3, pp. 535–542.     

Raman spectra of HfS3

We report the first order Raman spectra of a one-dimensional semiconducting compound HfS₃ at 300 and 77 K. The detected phonons are associated with the different point group symmetries involved in the crystal's structure.     

Raman spectra of ZrS3

We report the first order Raman spectra of a one-dimensional semiconducting compound ZrS₃ at 300 and 77 K. Four phonons have been detected and associated with the crystal's symmetry.     

The vapor-phase infrared and Raman spectra of p-difluorobenzene (h4) and (d4)

This new study of the vapor-phase infrared and Raman spectra of p-difluorobenzene (h₄) and (d₄) includes assignments from the high-resolution electronic spectrum, from fluorescence spectra, and one assignment from the two photon electronic spectrum. A new set of frequencies and assignments has been made for the fundamentals of this important intermediate-sized molecule. The most important changes concern the assignments previously made for the lowfrequency a_u mode (ν₈), two members of the b_2u class (ν₁₉ and ν₂₀), and one very important change for the lowest frequency fundamental of the b_3u (out-of-plane) class (ν₃₀), which has been observed directly in the far infrared. The results are all corroborated by the assignments of the perdeuterated analog where changes in previous assignments of Fermi resonance pairs have also been made. Some interesting differences between the Raman spectra of the vapor and the liquid perproto compounds have not been adequately explained in this study.     

A note on the Raman spectra and structure of Asx S100−x (x ⩾ 40) glasses

A recent paper in this journal by Slade and Zallen states that the present authors have suggested that actual microcrystals of β-As₄S₄ are present in vapour-deposited films of As₂ S₃. This is a mistaken interpretation of our previous work and in correcting the record we make some additional observations on the Raman spectra and structure of glasses in the As-S system. It is concluded that the Raman data is inconclusive on the existence, or otherwise, of phase-separated crystals.     

Argon matrix Raman and infrared spectra of SF5Cl,SF5Br,and S2F10

Infrared and laser-excited Raman spectra of SF₅Cl, SF₅Br, and S₂F₁₀ have been observed in dilute argon matrices and in the solid phase at 8 K. The first vibrational assignment of the SF₅Br molecule and assignments for the ν(SCl), ν(SBr), and ν(SS) modes in SF₅Cl, SF₅Br, and S₂F₁₀ are presented. The chlorine isotopic components of the SCl stretch in SF₅Cl have been resolved. The Raman spectrum of SF₅Br, which has not been reported previously, is discussed.     

Raman and far-infrared spectra of NaCrS2

The Raman and far-infrared spectra of the layer structure compound NaCrS₂ have been investigated. Two Raman active modes have been identified and their observed symmetries are in accord with the R$\text{3}$m space group symmetry of NaCrS₂. Three of the four predicted infrared active modes have been observed. One of the infrared modes appears as a strong reststrahlen band indicating that the bonding in NaCrS₂ is partially ionic.     

Raman and infrared spectra of ZnSiAs2

The optical phonons at k = 0 of ZnSiAs₂ have been investigated by Raman scattering and infrared reflectivity measurements at 300 K. Eleven of thirteen expected optically active phonons have been observed and identified with respect to their symmetry types. The phonon frequencies appear in the range from 415 cm^-1 to 75 cm^-1 with predominant polar modes at 400 cm^-1 (gG₅), 389 cm^-1 (Γ₄) and 242 cm^-1 (Γ₄). The dielectric dispersion for E ⊥ c and E 6 c has been determined by Kramers-Kronig integrations.     

The polarized infra-red and Raman spectra of Mg(OH)2 and Ca(OH)2

The complete polarized infra-red and Raman spectra of single crystals of calcium and magnesium hydroxide are presented. The results are largely in disagreement with those of previous workers both with regard to frequencies and to symmetry assignments. The assignments have been confirmed by study of the spectra of the deuterated counterparts of the crystals. The implications of the results for previous calculations of the dispersion curves are stressed. It is shown that there is little mixing of rotatory and translatory character among the external modes of vibration and a discussion of the origin of the Davydov splitting of the internal modes is given. The complex combination bands observed in the infra-red absorption spectrum are discussed and compared with neutron diffraction spectra.