Journal ArticleDOI
Calorimetric study of proton tunneling in solid 5-bromo-9- hydroxyphenalenone and deuteration-induced phase transitions in its deuteroxy analog
TLDR
In this article, a tunnel splitting of (64±2)cm−1 associated with the quantum mechanical motion of the hydrogen atom in the intramolecular O-H-O hydrogen bond was derived along with the Debye temperature 60.8 K and two Einstein temperatures 131.4 K.Abstract:
The heat capacities of 5-bromo-9-hydroxyphenalenone (BHP) and its deuteroxy derivative (BDP) were measured at temperatures between 2 and 310 K. The heat capacity of BHP is a smooth function of temperature and that of BDP has two peaks at 21.3 and 33.9 K. By analyzing the data on BHP, a tunnel splitting of (64±2) cm−1 associated with the quantum mechanical motion of the hydrogen atom in the intramolecular O–H–O hydrogen bond was derived along with the Debye temperature 60.8 K and two Einstein temperatures 131.4 (nondegenerate) and 210.4 K (doubly degenerate). The enthalpy change of 225 J mol−1 and entropy change of 6.8 J K−1 mol−1 were determined for the total thermal effects associated with the two phase transitions in BDP. The value of the transition entropy is consistent with the twofold disorder in the high temperature phase. The tunneling energy and transition enthalpy satisfy an inequality demanded, on the assumption that the potential energies experienced by the proton and deuteron are the same, by ...read more
Citations
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Theory of Ferroelectric Phase Transition in KHzP04 Type Crystals. I
TL;DR: In this article, a theory of the phase transi- tion is developed under the assumption that the ferroelectric behavior of this substance is due to cooperation of the ionic displacements, the interactions between ions and protons and the tunneling motion of protons.
Journal ArticleDOI
A formulation and numerical approach to molecular systems by the Green function method without the Born–Oppenheimer approximation
TL;DR: In this article, a new numerical scheme for the non-Born-Oppenheimer density functional calculation based upon the Green function techniques within the GW approximation for evaluating molecular properties in the full quantum mechanical treatment was proposed.
Book ChapterDOI
Tautomerism in the Solid State
Tadashi Sugawara,Isao Takasu +1 more
TL;DR: In this paper, the authors describe the potential profile of proton transfer along the reaction coordinate of the tautomerization in the solid state, focusing on the potential profiles of the proton tautomers.
Journal ArticleDOI
Proton tunnelling and deuteration-induced phase transitions in hydrogen-bonded crystals
TL;DR: In this article, the appearance of new crystalline phases at low temperature related to deuterium substitution is discussed and mechanisms of the isotope effect discussed and the role of proton tunnelling is discussed.
Journal ArticleDOI
Thermodynamic properties of chiral liquid crystalline material (S)-4-(2-methylbutyl)-4′-cyanobiphenyl (5∗CB)
TL;DR: In this article, the physical properties and dynamics of (S)-4-(2-methylbutyl)-4′-cyanobiphenyl (5∗CB) were investigated by adiabatic calorimetry between T = 5 and 350 K.
References
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Journal ArticleDOI
Optimization of parameters for semiempirical methods I. Method
TL;DR: In this paper, a new method for obtaining optimized parameters for semi-empirical methods has been developed and applied to the modified neglect of diatomic overlap (MNDO) method.
Journal ArticleDOI
Theory of Ferroelectric Phase Transition in KH2PO4 Type Crystals. I
Theory of Ferroelectric Phase Transition in KHzP04 Type Crystals. I
TL;DR: In this article, a theory of the phase transi- tion is developed under the assumption that the ferroelectric behavior of this substance is due to cooperation of the ionic displacements, the interactions between ions and protons and the tunneling motion of protons.
Journal ArticleDOI
Fluorescence and phosphorescence of 9-hydroxyphenalenone in solid neon and its hydrogen tunneling potential function
TL;DR: In this paper, the absorption and emission spectra of 9-hydroxyphenalenone in solid neon have been studied, showing that the tunneling splitting in the double minimum potential is relatively slow and extensive unrelaxed fluorescence.