Liquid-expanded to liquid-condensed phase transition in polyelectrolyte monolayers on the aqueous KBr solution. 2. Temperature dependence

1987 ◽  
Vol 20 (5) ◽  
pp. 1056-1060 ◽  
Author(s):  
Masami Kawaguchi ◽  
Sadanori Itoh ◽  
Akira Takahashi
Keyword(s):  
Phase Transition ◽  
Temperature Dependence ◽  
Condensed Phase

NQR and Crystal Structure of 4,5-Dichloroimidazole, C3H2N2Cl2

1992 ◽  
Vol 47 (1-2) ◽  
pp. 177-181 ◽  
Author(s):  
Shi-Qi Dou ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Unit Cell ◽  
Space Group ◽  
Temperature Range ◽  
Temperature Coefficients ◽  
Group D

AbstractThe two line 35Cl NQR spectrum of 4,5-dichloroimidazole was measured in the temperature range 77≦ T/K ≦ 389. The temperature dependence of the NQR frequencies conforms with the Bayer model and no phase transition is indicated in the curves v ( 35Cl)= f(T). Also the temperature coefficients of the 35Cl NQR frequencies are "normal". At 77 K the 35Cl NQR frequencies are 37.409 MHz and 36.172 MHz and at 389 K 35.758 MHz and 34.565 MHz. The compound crystallizes at room temperature with the tetragonal space group D44-P41212, Z = 8 molecules per unit cell; at 295 K : a = 684.2(5) pm, c = 2414.0(20) pm. The relations between the crystal structure and the NQR spectrum are discussed.

NQR, NMR, and X-ray crystal structure studies of [4-C2H5-C6H4NH3]2MBr4 (M=Zn, Cd)

2018 ◽  
Vol 73 (9) ◽  
pp. 611-616
Author(s):  
Hideta Ishihara ◽  
Hisashi Honda ◽  
Ingrid Svoboda ◽  
Hartmut Fuess
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Temperature Dependence ◽  
Benzene Ring ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Unit Cell ◽  
Organic Layers ◽  
Nuclear Magnetic Resonance Spectra ◽  
Quadrupole Resonance

AbstractThe crystal structure of [4-C2H5-C6H4NH3]2ZnBr4 (1) has been determined at 150(2) K: triclinic, P1̅, a=724.82(2), b=1194.20(4), c=1322.26(4) pm, α=74.151(3), β=80.887(3), γ=80.434(3)°, and Z=2. There are two crystallographically independent cations in the unit cell of 1: one has its benzene ring perpendicular to the crystallographic a axis of the unit cell and the other one has its benzene ring perpendicular to the c axis. These cations are alternatingly located along the c axis and form organic layers, and the ZnBr4 anions form inorganic layers in between. Zn–Br···H–N hydrogen bonds are formed between cations and anions. In accordance with the crystal structure, four nuclear quadrupole resonance (NQR) lines of 81Br were observed. The temperature dependence of the 81Br NQR frequencies between 77 and 320 K shows a peculiar feature which is not due to a structural phase transition. The measurement of 13C nuclear magnetic resonance spectra at around T=340 K indicates a redistribution of cations. The temperature dependence of 81Br NQR frequencies and differential thermal analysis measurements show that [4-C2H5-C6H4NH3]2CdBr4 (2) undergoes a structural phase transition at around 190 K.

scholarly journals FTIR Spectra of n-Octanol in Liquid and Solid States

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
A. Vasileva ◽  
P. Golub ◽  
I. Doroshenko ◽  
V. Pogorelov ◽  
V. Sablinskas ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Ftir Spectra ◽  
Ftir Spectrum ◽  
Structure Transformation ◽  
Temperature Range ◽  
Solid States

The investigation of the temperature dependence of FTIR spectrum of n-octanol in the temperature range from −150°C to 50°C is presented. The observed changes in the registered spectra during gradual heating of the sample were analysed. The structure transformation at the phase transition from solid to liquid phase is detected.

The temperature dependence of the photoinduced soft mode in Sn2P2S6 crystal

2019 ◽  
Vol 33 (08) ◽  
pp. 1950061
Author(s):  
K. A. Brekhov ◽  
N. A. Ilyin ◽  
E. D. Mishina ◽  
P. A. Prudkovskii ◽  
G. Kh. Kitaeva
Keyword(s):  
Phase Transition ◽  
Femtosecond Laser ◽  
Curie Temperature ◽  
Temperature Dependence ◽  
Oscillation Frequency ◽  
Phonon Mode ◽  
Soft Mode ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Curie Temperature Tc

In this paper, we present the results of the temperature dependence studies of the photoinduced phonon mode which appears in a ferroelectric-semiconductor Sn2P2S6 (SPS) crystal under the influence of femtosecond laser pulses. We show that its behavior reminds the soft mode one near the phase transition. However, the observed decrease in the oscillation frequency in the vicinity of Curie temperature Tc is much weaker than previously reported. This can be explained by the shadowing of the pure soft mode by its interaction with other photoinduced modes.

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