Temperature dependence of line frequencies in the vibrational spectra of condensed media

1986 ◽  
Vol 44 (5) ◽  
pp. 494-497
Author(s):  
S. A. Kirillov
Keyword(s):  
Temperature Dependence ◽  
Vibrational Spectra ◽  
Condensed Media

The Vibrational Spectra of NH4VO3 at Elevated Temperatures and Pressures

1987 ◽  
Vol 42 (7) ◽  
pp. 843-852 ◽  
Author(s):  
A . M. Heyns ◽  
M. W. Venter ◽  
K.-J. Range
Keyword(s):  
Hydrogen Bonds ◽  
Temperature Dependence ◽  
Vibrational Spectra ◽  
Elevated Temperatures ◽  
Structural Data ◽  
Volume Effect ◽  
Ambient Conditions ◽  
Hydrogen Bond Interactions ◽  
Diamond Anvil ◽  
Pressure Changes

Abstract Results obtained from the vibrational spectra of NH4VO3 and its deuterated analogues show that at least two types of hydrogen bond interactions can be identified at am bient conditions. In accordance with the structural data on NH4VO3 (F. C. Hawthorne and C. Calvo, J. Solid State Chem. 22, 157 (1977)) these interactions are assigned to normal, strong hydrogen bonds and weaker bifurcated ones, respectively. The temperature dependence of some of the N -H bands indicates that the normal hydrogen bonds decrease in strength with increasing temperatures, while the bifurcated ones tend to increase in strength. The NH4+ ions do not show fluxional behaviour at ambient conditions and even the bifurcated hydrogen bonds are of the type that is dominated by acceptor strength of the anions and not by a volume effect. The Ram an active NH4+ vibrations are very weak compared to the V - O modes and could not all be observed in the highpressure diamond anvil cell. The temperature dependence of the V - O Ram an active modes suggests that changes in the crystals of NH4VO3 brought about by the application of heat mainly involve the O -V -O angles, while pressure changes are mostly accommodated by changes in the V -O bridging bonds and O -V -O bridging angles.

Zur Elektronenstruktur hochsymmetrischer Komplexe der Lanthaniden und Actinoiden, I Magnetismus und Schwingungsspektren von Tris(tetraäthylammonium)-hexaisocyanato-ytterbium(III) / The Electronic Structure of Highly-Symmetrical Lanthanide and Actinide Complexes, I Magnetism and Vibrational Spectra of Tris(tetraethylammonium)-hexaisocyanate-ytterbium(III)

1976 ◽  
Vol 31 (1) ◽  
pp. 1-11 ◽  
Author(s):  
H.-D. Amberger ◽  
R. D. Fischer ◽  
G. G. Rosenbauer
Keyword(s):  
Magnetic Susceptibility ◽  
Electronic Structure ◽  
Temperature Dependence ◽  
Crystal Field ◽  
Vibrational Spectra ◽  
Spectroscopic Analysis ◽  
Raman Spectroscopic ◽  
First Order ◽  
Splitting Factor ◽  
Raman Spectroscopic Analysis

The results of a combined infrared and Raman-spectroscopic analysis of the compounds [N(C2H5)4]3[Ln(III)(NCO)6] (Ln = Yb, Lu) confirms the assumption that the central ion Ln3+ is octahedrally surrounded by six linear isocyanate ligands. The recently determined temperature dependence of the magnetic susceptibility of the Yb-complex in the range 1.0 < T < 300.2 K is compatible with the crystal field (= CF) splitting pattern: 0 = Ε(Γ6) < Ε(Γ8) < Ε(Γ7) ≪ Ε(Γ'8) < Ε(Γ'7) and a spectroscopic splitting factor |gexp(Γ6)| = 2.576 [i.e. k(tlu) = 0.955].Using the cubic first-order CF-functions, the energy differences ΔE(Γ8-Γ6) and ΔΕ(Γ7-Γ6) are fixed at 277 ± 10 and 650 ±130 cm-1 respectively. On this basis, the estimated ratio B4°/B6° of the two underlying cubic CF-parameters is discussed in terms of both “electrostatic” and “covalency” effects. This analysis has been used to interpret the paramagnetism of Cs2NaYbCl6 in terms of much larger CF-parameters than previously suggested

Temperature Dependence of Stability of Copper Clusters

2016 ◽  
Vol 230 (5-7) ◽  
Author(s):  
Valeri G. Grigoryan ◽  
Michael Springborg
Keyword(s):  
Temperature Dependence ◽  
Vibrational Spectra ◽  
Copper Clusters

AbstractPreviously we have determined the lowest-energy structures and full vibrational spectra of Cu

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