I want to carry out geometry optimization of silver supported catalyst on alumina (Ag/Al2O3) using material studio Dmol3 tool. However for my current parameter set the job has not been successful. Any suggestion will be highly appreciated
I'm not a Dmol3 guy, but generally, in order to generate meaningful answers in such cases, please include the following information:
1) What methods have you been trying to use? (functional, basis set, other settings)
2) What was not successful about the job? Does the resulting geometry make no sense, does it abort (then please post the error message), does it get stuck without aborting?
Below are the configurations
Functional: LDA (local-density approximation)
Exchange correlation: PWC
Functional: LDA
Energy convergence: 0.001Ha
max.force: 0.02Ha/Å
max.displacement:0.001Å
max.iterations:200
max.stepsize:0.3Å
Basis set:DND
Basis file:3.5
Scf tolerance:0.001
As regards, the second question asked, by jürgen weippert, the error message is "SCF not converging"
Ah, OK, "SCF not converging" is software-unspecific.
If the self-consistent field is not converging, possible reasons may be:
a) the starting geometry is far from optimal which may be not convergence-friendly. Preoptimization, e.g. with a semiempiric method, may help here.
b) the initial guess wavefunction is non-ideal.I don't know what Dmol3 offers here, other tools allow you to check the occupation numbers, use different guess types or apply Fermi smearing or damping.
c) the multiplicity of the calculation doesn't match the scenario.
[d) using a smaller basis set or simpler functional would also be an option, but since you're already on LDA level, you are already on the simplest level of DFT and DND is not that big of a basis set.].
A brute force way would also simply increase the number of iterations, but that has helped me exactly once so far.
📷
You
i run simulation on materials studio using forcite module but the molecules are not interacting they are just vibrating how to deal with this issue ?
Umm E Kalsoom I don't have experience on materials studio, either, but what kind of simulation have you started? If you have started a calculation of vibrational frequencies, that's the expectation. Equally, if you start an MD and choose a low temperature, there should also not be happening more than mild displacements from the equilibrium geometry.
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