Which temperature effects are you thinking of? The usual approach is either to do a thermodynamics calculation, which will use the phonons within the quasi-harmonic approximation, or to perform a molecular dynamics simulation.

Dear Philip James Hasni:

I am trying to use phonon within the quasi-harmonic approximation but I have no idea ho to perform such calculations. just to mention that I am using materials studio 7.0.

Thank you for answering my question

I haven't done that within Materials Studio, but from a CASTEP perspective you set the task to "thermodynamics" in the .param file, and it will compute the vibrational free energy across a temperature range controlled by the parameters:

THERMO_T_START Starting temperature

THERMO_T_STOP Final temperature

THERMO_T_SPACING Temperature spacing

THERMO_T_NPOINTS Number of points in temperature interval

Is that what you had in mind, or were there other quantities you were interested in?

CASTEP 7 is rather old now, CASTEP 20 is the current version! I recommend you get a (free) academic licence and upgrade. We try hard to maintain backwards compatibility, so all your CASTEP input files should work fine.

Thank you Philip for your answer, I am trying to study the influence of temperature on the electronic properties of nano- structure (band gap). I have DMOL3 and CASTEP .

You can either:

1. Compute the phonons, populate the displacement modes randomly using a Bose-Einstein distribution with your target temperature, and then compute the band-structure for those displaced geometries.

Advantages: quick to repeat for different temperatures

Disadvantages: phonon calculation is expensive; restricted to quasi-harmonic approximation

2. Perform an ab initio molecular dynamics calculation at the target temperature, and sample the band-structure

Advantages: includes all orders of phonons; relatively quick to sample the ensemble

Disadvantages: phonons are wavelength-truncated by the simulation cell; not straightforward to recompute at a different temperature without doing another MD run; temperature fluctuations will be large unless you have a lot of atoms

Thank you Philip

I think the second choice might work, I will try it.

Appreciate your help

Hello, thank you for your efforts.

I am using CATSEP Material Studio: I have a problem knowing the temperature in the program.

Do our calculations according to the room temperature.

How can the temperature be controlled?

Where is the temperature changed in the program?

If possible, a video to explain.

Thank you all