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Tanya Faltens

Why does 6 not look octahedral?

When I choose n = 6 particles, I expect to see an octahedral arrangement around the central atom, but this is not what I see. Is there something else going on that I am missing? Thank you! (n=3, 4, 8 look OK to me)

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    Baudilio Tejerina

    Hi Tanya.

    That’s an excellent observation.

    The reason is that the algorithm that searches for optimum structure has not found any new (lower in energy than the last fond) after certain number of trials. I thing that the limit is 2000. After that number is reached, the program stops and reports the structure of lowest energy.

    In the case of N=6, it happens that the structure found does not correspond to the one we would’ve expected: Octahedral.

    What we should learn from this is that the algorithm implemented in the tool gives us the configuration of energy lower than or equal to the initial one but, it does not warrant it is the lowest.

    Anyway, I’ve updated the program so that, besides the automatic generation of the initial guessed geometry, you can input and try your own initial structure. Precisely, I’ve included as demo the example of an octahedron. If you run this example, you’ll see that the initial distribution (a perfect octahedral distribution) and the final is the same.

    Regards, And THNAKS for the observation and report…


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