# Questions tagged [entropy]

Questions relating to entropy. The entropy S, of a physical system, is related to the number of possible microscopic configurations of that system. It is also a measure of disorder in a physical system.

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### Computing the rotational entropy in RRHO approximation

I am implementing the computation of Gibbs energies by their molecular parameters (structure, frequencies) in my program Chemcraft (the main task is the possibility to cut small frequencies which ...
62 views

### Computation of thermodynamic functions of molecules by molecular parameters

I want to implement in my program Chemcraft the computation of entropy and Gibbs energy of molecules in approximation "rigid rotor - harmonic oscillator", by the molecular parameters (...
157 views

### Rigorous definition of electronic entropy

Suppose we want to compute the exact standard molar electronic entropy of helium at a finite but not very high temperature, say $T = 298.15 \textrm{ K}$. By "standard" I mean the standard ...
41 views

### Atomic Packing Fraction [closed]

I need to calculate excess entropy of mixing for a particular system of alloy. The excess entropy of mixing is dependent on temperature and it takes into account this temperature dependence by using ...
143 views

### Correlation Functions in the Cluster Variation Method [closed]

I've been referring to Dr Mohri's paper [DOI: 10.1007/s11837-013-0738-5] for the cluster variation method (CVM). I wish to calculate the configurational entropy of a binary FCC system. Cluster ...
724 views

### How to calculate the conformational entropy of a molecule?

Introduction It is know that the entropy of a system can be calculated using the formula (1): \begin{equation} \label{eq:entropy_Boltz} S = {k_B}\ln \Omega\tag1 \end{equation} where $k_B$ is the ...
185 views

### VASP output energy

Which VASP output energy, after sigma -> 0 or before, do you use when combining with zero point energy and vibrational entropy obtained via vtst tools? (Vtst tools provide the vibrational frequencies ...