Questions tagged [semi-empirical-method]

For questions about methods (typically in electronic structure theory) that use experimental parameters as part of their formulation

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5 votes
2 answers
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SCF not converging during RHF/STO-3G geometry optimisation

I'm new in the field of QM methods and I've run into a problem for which I can't find a solution online. I have tried with different basis sets, I've raised the maximum number of iterations and number ...
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6 votes
2 answers
128 views

Symmetry-preserving low-level structural relaxation

I would like some suggestions on how to do structural relaxation (while I'm at it, let me list some synonyms for search exposure - geometry optimization, structural refinement, energy minimization etc)...
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7 votes
1 answer
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Is it possible to get complex numbers as solutions for a secular determinant in simple Hückel method (SHM)?

Past semester we revisited the Hückel molecular orbital theory at class. One day I was trying to solve some problems with SymPy, a Python module that is a computer algebra system (CAS), and noticed ...
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19 votes
2 answers
248 views

State of the art in computational materials design

With the advent of more computational power than ever in the recent years, interest in in silico design of interesting compounds has grown as well. I am wondering about the state of the art for the ...
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13 votes
1 answer
151 views

Semi-empirical software for bands calculations

In Semiconductor Physics, one of the main parameters of interest is the band gap. It is known that, in DFT, there are functionals that underestimate it. I came across the MOPAC program, a semi-...
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27 votes
3 answers
458 views

Where is the extended Hückel method (EHM) still used today?

The extended Hückel method (EHM) proved to be very useful through time, but there are better and affordable models today. One interesting thing about the model is the independence of the Hamiltonian ...
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