No description
-
November 27, 2014 (v1)PublicationUploaded on: March 27, 2023
-
December 13, 2017 (v1)Publication
A computer procedure has been developed to calculate second-order thermal diffuse scattering (TDS) intensity for molecular crystals from latticedynamical calculations with an atom-atom potential in the Born-von K~irmfin formalism. It is applied to monoclinic phenothiazine and different contributions to second-order TDS intensity,...
Uploaded on: December 4, 2022 -
April 24, 2017 (v1)Publication
The lattice dynamics of potassium selenate is analyzed using a rigid-ion model with the selenate groups reduced to rigid bodies. The interatomic forces have been adjusted only using static structural data. The number of adjustable parameters varies from two to five. Such a simple model is already sufficient to reproduce semiquantitatively the...
Uploaded on: March 27, 2023 -
December 15, 2017 (v1)Publication
Mr=324.4, orthorhombic, P212t2 ~, a= 32.150(5), b=10.215(1), c=4.805(1)A, V= 1578.0 (4)/~3, Z = 4, D x = 1.36 Mg m -a, 2(Cu Ka) = 1.5418A, #=1.953mm -1, T=300K, final R= 0.050 for 1361 observed [I>2tr(I)] independent reflexions. The sugar ring adopts a conformation intermediate between envelope 2E and twist 2T forms. The orientation of the...
Uploaded on: March 27, 2023 -
December 13, 2017 (v1)Publication
First- and second-order thermal diffuse scattering (TDS) intensities are calculated in the long-wave approximation allowing for dispersion (LWD) in monoclinic phenothiazine from polarization vectors and lattice-mode frequencies obtained from lattice dynamical calculations within the harmonic approximation and the external Born-von K~irmfin...
Uploaded on: March 27, 2023 -
December 13, 2017 (v1)Publication
A computer program has been developed to calculate first-order thermal diffuse scattering (TDS) intensity from eigenvectors and eigenvalues of the dynamical matrix obtained within the harmonic approximation with an atom-atom potential function and the external Born-yon Kfirmfin formalism. It is applied to monoclinic phenothiazine and correction...
Uploaded on: December 5, 2022 -
December 14, 2017 (v1)Publication
M r = 306.4, monoclinic, P21, a = 14.686 (6), b=5.359(4), c=9.439(3) A, fl=98.68(3) ° , V= 734.4 (7)/I,3, Z = 2, D x = 1.38 Mg m -3, 2(Mo Kct) = 0.7107 A, /t = 0-22 mm -1, F(000) = 324, T= 300 K, final R=0.042 (wR=0.037) for 1987 observed independent reflections. The sugar ring has a conformation intermediate between 3T 2 and 3E. The...
Uploaded on: December 4, 2022 -
December 14, 2017 (v1)Publication
A computer program has been developed to study the lattice dynamics of molecular crystals in the harmonic approximation with the external Born-yon KS.rm~n formalism and an atom-atom potential function. Dispersion curves are obtained for monoclinic phenothiazine together with frequency distribution functions and external mode contribution to...
Uploaded on: December 4, 2022 -
December 14, 2017 (v1)Publication
Mr=346-4, orthorhombic, P212121, a= 7.600(1), b= 11.132(2), c=20.767 (3)A, v= 1756.9(5)A 3, z=4, Dx=1.31Mgm -3, 2(CuKct) =.1.5418/k, /~= 1.67mm -1, F(000)=728, T= 300 K. Final R = 0.049 for 1531 observed independent reflections. The benzimid~zole bicycle is quasi-planar, the dihedral angle between the two fused rings being 1.6 (2) °. The...
Uploaded on: March 27, 2023 -
December 14, 2017 (v1)Publication
Mr=334.4, orthorhombic, P212~2 ~, a= 9.366(4), b=20.616(5), c=9.137(4)A, V= 1764 (1) A 3, Z = 4, D x = 1.26 Mg m -3, 2(Mo Ka) = 0.7107 A, g = 0.18 mm -~, F(000) = 704, T= 300 K, final R--0.056 (wR =0.052) for 1979 observed reflections [I > 2a(/)]. The furanose ring is approximately planar because of the double bond, 1.289 (9) A, which affects...
Uploaded on: March 27, 2023 -
April 19, 2017 (v1)Publication
The experimental curves giving the temperature dependence of the thermal conductivity of glassy selenium are considered in detail. The observed behavior can be taken into account quantitatively if the densities of states for short-wavelength phonons as well as for low-energy librations arising from computer simulations are used for the...
Uploaded on: December 4, 2022 -
May 8, 2017 (v1)Publication
The dynamics of crystalline glycerol are studied by means of Raman spectroscopy and lattice dynamics calculations employing a semiflexible model to represent the low-lying molecular vibrations. The latter is validated against structural, thermodynamic, and spectroscopic data. The results serve to set an absolute frequency scale for glassy...
Uploaded on: December 4, 2022 -
April 19, 2017 (v1)Publication
The Europium compound Eu2BaCoO5 has been studied by means of Raman and x-ray-absorption spectroscopies. The eigenfunctions and frequencies of the optical normal modes have been calculated from an adequate potential showing good accordance with the observed phonons. In addition to Raman-allowed normal modes, several infrared and luminescence...
Uploaded on: December 4, 2022 -
May 8, 2017 (v1)Publication
The existence of an orientationally disordered cubic phase of solid ethanol is revealed by x-ray diffraction and Raman spectroscopic measurements. Such a phase, whose existence was postulated some time ago on the basis of specific-heat measurements, is produced by quenching below some 95 K a plastic crystal formed upon melting and subsequent...
Uploaded on: March 27, 2023 -
April 19, 2017 (v1)Publication
The elastic and total (energy-integrated) structure factors for glassy selenium have been measured by means of neutron spectroscopy within the temperature range 15 KT310 K. The correlated nature of the atomic vibrations gives rise to marked features in the total (energy-integrated) inelastic structure factors defined as the difference between...
Uploaded on: March 27, 2023 -
April 20, 2017 (v1)Publication
The low-frequency dynamics of a molecular glass former has been investigated by means of inelastic neutron scattering from a mostly incoherent sample as well as by computer molecular-dynamics simulation. The mode assignments have been carried out using the neutron data for the polycrystal as well as by means of the analysis of the density of...
Uploaded on: December 2, 2022 -
April 19, 2017 (v1)Publication
The microscopic low-frequency dynamics of glassy selenium is investigated by means of the concurrent use of neutron inelastic scattering and computer simulations. A separation of the dynamic response in terms of intra- and interchain processes is achieved from the analysis of the simulation results. The S(Q,E) dynamic structure factors are...
Uploaded on: December 4, 2022 -
June 7, 2022 (v1)Publication
The collective dynamics of liquid methanol‐d4 is studied by means of molecular‐dynamics simulation. The model potential is validated by means of lattice energy calculations and shows a very good agreement with the experimentally obtained crystal structure. Center‐of‐mass density and momentum fluctuations are investigated in the (Q,ω) region...
Uploaded on: March 25, 2023 -
July 24, 2017 (v1)Publication
The dynamics of the freezing transition of the rotator phase crystal of ethanol into its orientational glass phase is monitored by measurements of molecular rotational components in the quasielastic neutron scattering spectrum. We demonstrate that phenomena observed at pico- and nanosecond scales can be mapped onto those shown by a model of...
Uploaded on: March 27, 2023 -
May 8, 2017 (v1)Publication
The reorientational dynamics within the rotationally disordered cubic plastic phase of solid ethanol is investigated by means of the concurrent use of computer molecular dynamics and quasielastic neutron scattering. Motions involving widely different time scales are shown to take place above the calorimetric "glass transition" which is centered...
Uploaded on: December 4, 2022 -
May 8, 2017 (v1)Publication
We report measurements of the temperature dependence of the sound attenuation and the fractional change in sound velocity for the glass (G) and orientational-glass (OG) phases of polymorphic ethanol. Strikingly similar behaviors are found for both phases despite the OG's underlying crystal (bcc) lattice. Such similarity, which is also revealed...
Uploaded on: March 27, 2023 -
April 19, 2017 (v1)Publication
In the title compound, C 5 H 14 N 3 + H 2 PO 4 ˇ , the cation has a central guanidinium fragment with a planar geometry, as expected for a central C sp 2 atom with a small charge delocalization along the three C–N bonds. The crystal packing is governed by hydrogen bonds so that the phosphate anions...
Uploaded on: December 4, 2022 -
April 7, 2017 (v1)Publication
The title compound, C 10 H 16 N + H 2 PO 4 H 2 O, crystallizes in the centrosymmetric space group P 2 1 / c with two independent molecules in the asymmetric unit. Therefore, nonlinear optical properties are absent. The crystal packing is governed by hydrogen bonds, so that the phosphate anions are linked head- to-tail, ...
Uploaded on: March 27, 2023