Results 271 to 280 of about 121,703 (314)

Helmholtz Free Energy of Peptide Hydrogen Bonds in Proteins

Journal of Molecular Biology, 1996
We estimate the Helmholtz free energy of peptide hydrogen bonds in native protein structures as a function of spatial separation between donor and acceptor atoms. The resulting potential function has a deep narrow well at H-bond contact but bond formation is hindered by a barrier and the net change in free energy is close to zero.
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Helmholtz Free Energy of an Anharmonic Crystal: A Green Function Approach

physica status solidi (b), 1971
AbstractThe thermodynamic Green function of a weak anharmonic crystal, obtained through the equation of motion method, has been used to derive an explicit expression for the interaction energy. The Helmholtz free energy (F) has been obtained by integrating this interaction energy over a formal coupling parameter. Under certain conditions the expression
R. C. Shukla, E. B. Muller
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Helmholtz Free-Energy Bounds from High-Temperature Series?

The Journal of Chemical Physics, 1970
In theoretical equation-of-state investigations an important goal is to obtain the Helmholtz free energy, from which other thennod)lnamic properties can be obtained. The Helmholtz free energy is hard to cal­ culate directly. A less ambitious goal is to relate the free energy for the system of interest to the properties of a simpler, well-understood ...
W. T. Ashurst, W. G. Hoover
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Helmholtz free energy for two-dimensional Lennard-Jones fluids

Chemical Physics, 1993
Abstract The Helmholtz free energy for two-dimensional Lennard-Jones fluids is calculated over a wide range of densities and temperatures from computer simulation results for the radial distribution function. The applicability to this calculation of the first-order Weeks-Chandler-Andersen theory, called the high-temperature approximation, is verified.
F. Cuadros, A. Mulero
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An instability in a hard-disc system in a narrow box (Helmholtz free energy)

Journal of Physics A: Mathematical and General, 1983
It is shown that a system of N (N to infinity ) hard discs (of diameter sigma ) in a narrow box, of width D (D< square root 3 sigma ) and length L=Nl, is unstable for a certain range of D and l when D is variable.
K W Wojciechowski, P Pieranski, J Malecki   +2 more
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A Free Energy Formulation of Music Generation and Perception: Helmholtz Revisited

2013
This chapter pursues the notion that, quintessentially, music enables the prediction of the unpredictable. Our focus is on the perception of music using ideas from theoretical biology and neuroscience to explain the nature of musical stimuli and their perceptual synthesis.
Karl J. Friston, Dominic A. Friston
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On Renormalized Einstein Phonons. II. The Diagrammatic Method and Helmholtz Free Energy

American Journal of Physics, 1972
The Helmholtz free energy (F) of interacting Einstein oscillators has been presented as a simple working example of the diagrammatic method. All those diagrams (ring type in the present case) that contribute to F have been included, and the resulting series has the form of a logarithmic expansion.
R. C. Shukla, E. R. Muller
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Helmholtz free energy of a cluster on the coherent substrate: Monte Carlo calculations

The Journal of Chemical Physics, 1995
Monte Carlo simulations of clusters on underlying substrate have been performed. A cluster free energy has been calculated for different substrate lattice parameters. Computing efforts have been focused on the case when a substrate lattice was approximately the same as a bulk crystal lattice consisting of the cluster molecules. The present calculations
Evgeni L. Zapadinsky, Markku Kulmala
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Absolute Helmholtz free energy of highly anharmonic crystals: Theory vs Monte Carlo

The Journal of Chemical Physics, 2012
We discuss the problem of the quantitative theoretical prediction of the absolute free energy for classical highly anharmonic solids. Helmholtz free energy of the Lennard-Jones (LJ) crystal is calculated accurately while accounting for both the anharmonicity of atomic vibrations and the pair and triple correlations in displacements of the atoms from ...
Lydia, Yakub, Eugene, Yakub
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Helmholtz Free Energy Equation of State Applied to Carbon at Megabar Pressures

AIP Conference Proceedings, 2006
We provide a simple form of a Helmholtz free energy equation of state that reproduces the Hugoniot of shock compressed porous carbon at megabar pressures. The equation of state consists of the modified Cowan ion EOS and a correction term related to the free energy that is independent of thermal motion.
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