Lattice dynamics of solid α-carbon monoxide

The lattice dynamics of α-CO is studied assuming a fully-ordered antiferro P2₁3 structure, using a potential model which includes electrostatic, dispersion and exchange interactions. The coupling of translational and librational motions leads to mixed modes at finite wave vectors and to anomalous acoustic dispersion. Anharmonic frequency shifts and the damping due to phonon—phonon interactions are evaluated for the zero wave vector modes. The single-particle potential wells for the high-frequency librational modes are investigated and suggest that translation—rotation coupling plays a primary role in the molecular reorientations.     

Lattice dynamics of the high-pressure monoclinic phase of solid carbon tetrachloride

Two intermolecular potential functions (models I and II), recently proposed for liquid CCI₄, are used to study the lattice dynamics of the monoclinic high-pressure solid, phase III. Model II agrees reasonably well with the measured Raman Spectrum.     

Complex formation of vinylidene chloride with hydrogen chloride in the solid phase at low temperatures

Moscow State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 170–174, March–April, 1992.     

Lattice oligomer dynamics

Exact results are obtained for the dynamics of short chains on the cubic lattice in the presence of excluded volume. The dynamics is used to evaluate the vector end-to-end length and squared length correlation functions. These functions are compared to those obtained by computer simulation by Kranbuehl and Verdier for longer chains. A coherent picture of the effects of excluded volume and chain length on the system properties sampled is found.     

Lattice dynamics to trigger low temperature oxygen mobility in solid oxide ion conductors

SrFeO(2.5) and SrCoO(2.5) are able to intercalate oxygen in a reversible topotactic redox reaction already at room temperature to form the cubic perovskites Sr(Fe,Co)O(3), while CaFeO(2.5) can only be oxidized under extreme conditions. To explain this significant difference in low temperature oxygen mobility, we investigated the homologous SrFeO(2.5) and CaFeO(2.5) by temperature dependent oxygen isotope exchange as well as by inelastic neutron scattering (INS) studies, combined with ab initio (DFT) molecular dynamical calculations. From (18)O/(16)O isotope exchange experiments we proved free oxygen mobility to be realized in SrFeO(x) already below 600 K. We have also evidence that low temperature oxygen mobility relies on the existence of specific, low energy lattice modes, which trigger and amplify oxygen mobility in solids. We interpret the INS data together with the DFT-based molecular dynamical simulation results on SrFeO(2.5) and CaFeO(2.5) in terms of an enhanced, phonon-assisted, low temperature oxygen diffusion for SrFeO(3-x) as a result of the strongly reduced Fe-O-Fe bond strength of the apical oxygen atoms in the FeO(6) octahedra along the stacking axis. This dynamically triggered phenomenon leads to an easy migration of the oxide ions into the open vacancy channels and vice versa. The decisive impact of lattice dynamics, giving rise to structural instabilities in oxygen deficient perovskites, especially with brownmillerite-type structure, is demonstrated, opening new concepts for the design and tailoring of low temperature oxygen ion conductors.     

Lattice dynamics of tetracyanoethylene

Lattice dynamics calculations for both crystalline forms of tetracyanoethylene are presented. The comparison of the calculated static and dynamical properties with the experimental data, leads us to suggest an improved parameter set for the “6-exp” potential function for crystals with cyano groups.     

Lattice dynamics of cuprous iodide

The lattice dynamics of cuprous iodide have been investigated on the basis of an ‘11-parameter’ rigid-ion model (RIM). The reported neutron scattering data of CuI are reasonably well decribed by the model, especially when an optimized procedure for the selection of parameters is used. Results are presented for the phonon dispersion curves of CuI. The critical point phonon (CPP) frequencies inferred from the model are shown to provide satisfactory assignments of the observed two-phonon features in the available Raman spectrum.     

Lattice dynamics of single-bonded cubic nitrogen

The first principle calculations of the lattice dynamical properties of the single-bonded cubic nitrogen were performed using the density-functional perturbation theory together with plane-wave expansion and nonlocal pseudopotentials. The equilibrium structure of the single-bonded cubic nitrogen was first evaluated via the minimization of the total energy. Then, the harmonic phonon dispersion curves and the density of phonon states of the single-bonded cubic nitrogen have been evaluated within the linear-response framework. Furthermore, the heat capacity, enthalpy, free energy, entropy and velocity of sound of the single-bonded cubic nitrogen were calculated.     

Microdynamics of solid anilinium chloride

Intraionic C₃ reorientation of the anilinium NH⁺₃ group was evidenced by measurements of the temperature dependence of the proton spin—lattice relaxation time, by rotating frame experiments and cw NMR data. Analysis of the results yielded a rotor hindering potential E = 33.6 kJ/mole and τ_o = 4 × 10⁻¹³ s.     

Lattice dynamics of InAs under hydrostatic pressures

The lattice dynamics of InAs under variable hydrostatic pressures is investigated on the basis of an ‘11-parameter’ rigid-ion model (RIM). The calculated phonon dispersion curves are in satisfactory agreement with the neutron scattering data (available for the TA modes only) measured at room temperature and atmospheric pressure. The one- and two-phonon densities of states functions and mode Gruneisen parameters have been computed at two arbitrary hydrostatic pressures. The effect of high pressure on the phonon dispersion curves is shown to lead to a typical ‘softening’ in the transverse acoustic modes and eventually to a phase trnasformation of the compound.     

Reaction of amidophosphites with hydrogen chloride

Conclusions The reaction of some mono-, di-, and triamidophosphites with HCl was studied at low temperatures. The amido group is replaced by chlorine in the first step of the reaction, apparently due to protonation of the nitrogen atom of the amidophosphite. The formation of P-protonated products in the case of the monoamidophosphites is due to the disproportionation of dialkyl chlorophosphites in excess HCl.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, September, 1977.     

Oxidation of hydrogen chloride with hydrogen peroxide in aqueous solution

Evolution of chlorine into the gas phase upon mixing of aqueous solutions of hydrogen chloride and hydrogen peroxide was studied. The threshold hydrogen chloride concentration corresponding to the onset of the chlorine evolution was determined.     

Tunneling in the loss of hydrogen chloride from isopropyl chloride cation

The unimolecular dissociation of isopropyl chloride cation has been investigated using mass-analyzed ion kinetic energy spectrometry. The C3H6*+ ion was the only product ion in the metastable dissociation. The kinetic energy release distribution for the HCl loss was determined. Ab initio molecular orbital calculations were performed at the MP2/6-311++G(d,p) level together with single point energy calculations at the QCSID(T)/6-311++G(2d,2p) level. The calculations show that the molecular ion rearranges to an ion-dipole complex prior to loss of HCl via a transition state containing a four-membered ring. The rearrangement involves H atom transfer. On the basis of the potential energy surface obtained for the loss of HCl and Cl*, the rate constants were calculated by transition-state statistical theories with considering tunneling effect. From the calculated result, it is proposed that the observed HCl loss would occur via tunneling through the barrier for isomerization to the ion-dipole complex, CH3CHCH2*+...HCl.     

On the difference between hydrogen fluoride and hydrogen chloride crystals

The geometrical and energetical parameters of hydrogen fluoride and hydrogen chloride crystals are calculated using the periodic Hartree–Fock method with 6-31G and 6-31G(d,p) basis sets. The comparison of the stabilisation energies reveals that HCl crystals are about 75% less stable than HF crystals. The activation energy for collective proton movements are computed and discussed in view of data of isolated infinite chains. The barriers of 13.1 and 40.0 kcal mol⁻¹ at 6-31G(d,p) level are found for HF and HCl crystals.     

The parameters of hydrogen chloride and hydrogen bromide direct-current glow-discharge plasmas

A comparative analysis of the parameters of HCl and HBr plasmas was performed by means of mathematical simulation, solving the Boltzmann kinetic equation in the one-component approximation. The specifics of the kinetics of the electron impact-induced processes and the composition of plasma charged species were analyzed.     

Reaction of p-menthadiene dioxide with hydrogen chloride

Conclusions When 1,2,8,9-diepoxy-p-menthane is reacted with HCl in ether under mild conditions, the 1,2-epoxy ring opens first in accordance with the conformational control of the reaction to form (–)-trans-2-hydroxy-1-chloro-8, 9-epoxy-trans-p-menthane from the cis dioxide or (–)-trans-1-hydroxy-2-chloro-8, 9-epoxy-trans-p-menthane from the trans dioxide. The opening of the 8,9-epoxy ring to form products of the addition of 2 moles of HCl takes place with difficulty.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 847–851, April, 1979.     

Penning ionization electron spectrometry of hydrogen chloride

An electron spectrometric study has been performed on HCl using metastable helium and neon atoms as well as neon resonance photons. High resolution electron spectra were obtained with two different beam apparatuses for a mixed He(2¹ S, 2³ S) beam, a pure He(2³ S) beam, and, for the first time, state-selected pure Ne(3s ³ P ₂) and pure Ne(3s ³ P ₀) beams, and for NeI resonance photons. For the system He(2³ S)+HCl the vibrational populationsP(υ′) of the formed HCl⁺ (X ²∏ _i , υ′) and HCl⁺ (A ²Ω⁺, υ′) ions are found to differ from the Franck-Condon factors for unperturbed potentials, indicating slight bond stretching in HCl upon He(2³ S) approach. For He(2¹ S)+HCl the vibrational peak shapes and vibrational populations are substantially different from the He(2³ S) case, pointing to an additional, charge exchanged interaction (He⁺+HCl^?) in the entrance channel of the former system. For the first time, we have detected the electrons in both the He(2¹ S)+HCl and He(2³ S)+HCl spectra associated with the major mechanism for the formation of Cl⁺ ions: energy transfer to repulsive HCl** Rydberg states, dissociating toH(1s) and autoionizing Cl**(¹ D ₂ nl) atoms. For both Ne(³ P ₂)+HCl and Ne(³ P ₀)+HCl, the populationsP(υ′) of both final molecular states HCl⁺ (X, A) agree closely with the Franck-Condon factors at the average relative collision energyē _coll=55 meV and, for HCl⁺ (A ²Ω⁺), also atē _coll=130 meV.