# Questions tagged [correlation-functions]

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### How exactly does one compute the vibrational density of states from the output of a molecular dynamics simulation?

There are many things that can be done with the output of a molecular dynamics simulation, but one of the more powerful things is the ability to compute the vibrational density of states (or the ...
• 3,464
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### 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 ...
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### What is autocorrelation time?

I'm writing this code of molecular dynamics about a pseudo-ideal gas in a box. The task is integrating the EOM for every atoms for a time-step dt fixed with the leapfrog method and measure the total ...
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### Derivation on correlation function and response functions in polymer physics

I am reading Introduction to Polymer Physics by Doi and I am having trouble understanding a derivation by him on the concentration fluctuations in polymer solutions. I have outlined his method and ...
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### What's the pair correlation function? What information does it contain? [closed]

This question is related to this VASP tutorial, in which the pair correlation function (or radial distribution function: RDF) is utilized to justify whether the solid silicon is melt by AIMD (ab-...
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### Deriving relations for a hard sphere phase diagram [closed]

In Torquato's book "Random Heterogeneous Materials", he has written: $$\frac{p}{\rho kT} = 1+2^{d-1}\eta g_2 (D^{+})\tag{1}$$ where $g_2(D^+)$ is the contact value from the right-side of the ...
• 4,141
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### Programming auto-correlation function calculation

I have a set of data (heat flow) values in x, y and z directions for which I have to calculate the auto-correlation function to get the thermal conductivity. I have written a small Fortran90 code but ...
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### 2D Infrared spectroscopy for bulk systems using molecular dynamics

There are some questions and answers (1,2) on this site regarding simple infrared and vibrational density of states calculations with molecular dynamics and there any simple algorithmic descriptions ...
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I have tried to calculate Residence time using the residence time auto-correlation function defined as $$R(t) = \frac{\langle h(0)h(t)\rangle}{\langle h(0)h(0)\rangle}$$ In the calculation, I have ...