Intermolecular potential energy functions and Gruneisen Parameters of simple molecular crystals

Chandrasekharan, V.; Farbre, D.; Thiéry, M. M.; Uzan, E.; Donkersloot, M. C. A.; Walmsley, S.H.

doi:10.1016/0009-2614(74)85416-3

Cited by 18 publications

(3 citation statements)

References 15 publications

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“…To take proper account of the volume dependence of the zero point energy for these modes, the corresponding Grtineisen parameters, Vi = -(~ In w i/~ In V), are incorporated. Values of w i and Yi were obtained respectively from the experimental data for ~= 0 frequencies measured at 15 K from neutron scattering [35] and experimental [36,37] and theoretical Griineisen parameters [34] for the external optical modes. For the internal optical modes, the zero point energy contribution was determined from the difference in vibrational energy between the measured modes in the solid and the molecular gas.…”

Section: Potential Well Regionmentioning

confidence: 99%

Towards an intermolecular potential for nitrogen

1984

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Section: Potential Well Regionmentioning

confidence: 99%

Towards an intermolecular potential for nitrogen

1984

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“…Before concluding the discussion of the Grüneisen parameters, we draw attention to the possible effect of coupling between internal and external modes on the Grüneisen parameter and its reflection of the anharmonicity of the crystal lattice potential [41,46,34,47]. Since the internal modes and external modes overlap in frequency range for HPTB and HPTB • 2CBr 4 , the temperature evolution of the calculated γ s could be influenced by mode coupling.…”

Section: Grüneisen Parametersmentioning

confidence: 99%

Additivity of guest and host properties in clathrates: a thermodynamic and Raman spectroscopic investigation of HPTB-based solids

Michalski

Perry

White

1996

J. Phys.: Condens. Matter

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The heat capacities of hexakis(phenylthio)benzene (abbreviated as HPTB) and the clathrate have been determined from 30 to about 300 K. In addition, the room-temperature Raman spectra have been obtained for both compounds. The Raman spectrum of is very closely approximated by the sum of the spectrum of HPTB and that of pure , indicating the additivity of the guest and host intramolecular interactions. These internal degrees of freedom dominate the heat capacity, and the present analysis shows the importance of the low-frequency modes. Over a wide range of temperature below 200 K, the calculated Grüneisen parameter of HPTB is higher than for .

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“…27,29 The same was postulated for the modes due to rigid-molecule librations. 30 Since both internal and external modes are present in CBr 4 , the temperature evolution of the calculated ␥ would be influenced by any coupling between internal and external modes.…”

Section: Grü Neisen Parametermentioning

confidence: 99%

A thermodynamic investigation of dynamical disorder in Phase II of CBr4

Michalski

White

1995

The Journal of Chemical Physics

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CBr 4 is an archetypal example of a pseudospherical molecule that can form an orientationally disordered phase ͑phase I, 320 KϽTϽ365 K͒. At lower temperatures, phase II is the stable phase; although it must be more ordered than phase I, different techniques give conflicting results concerning order in phase II. In order to investigate dynamical disorder in phase II, the heat capacity of CBr 4 has been measured in the temperature range 30-305 K. No phase transitions were found in this region. The calculated heat capacity, with contributions due to low-frequency translation and rotational-vibrations of the rigid CBr 4 molecules, as well as internal motions, fits the experimentally derived C v data to within 3%. Virtually full excitation of rigid molecule rotation-vibrations at very low temperatures ͑ϳ45 K͒ is consistent with the observation of a low-temperature elevation in the calculated Grüneisen parameter.

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Intermolecular potential energy functions and Gruneisen Parameters of simple molecular crystals

Cited by 18 publications

References 15 publications

Towards an intermolecular potential for nitrogen

Towards an intermolecular potential for nitrogen

Additivity of guest and host properties in clathrates: a thermodynamic and Raman spectroscopic investigation of HPTB-based solids

A thermodynamic investigation of dynamical disorder in Phase II of CBr4

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