Appropriate rgkmax value for Au

Elk Users
  • mosahhar

    mosahhar - 2012-12-10

    What's appropriate rgkmax value for heavy metals esp Au?
    In general, Is there any way to determine rgkmax for elements?
    Thank you in advance

  • Ken Roberts

    Ken Roberts - 2012-12-11

    Dear Mosahhar,

    I'm most definitely not an ELK or DFT expert, so I can only report my own small experience, not give well-founded advice.

    A value of at least rgkmax = 10.0 seems to be necessary to calculate the ground state of fcc gold with LSDA method (xctype 3).  Lesser values of rgkmax have "sawteeth" in the curve of total energy vs lattice spacing.  I also use gmaxvr = 40.0 for similar reason.

    Even larger values of those parameters may be appropriate.  I'm still exploring the sensitivity of curve smoothness vs the choice of the three parameters, ngridk, rgkmax, and gmaxvr - most of my explorations being done with xctype = 3 (LSDA).

    Hope that helps.  I wil be interested in hearing about anything you observe.

    Best wishes,
    Ken Roberts

  • mosahhar

    mosahhar - 2012-12-11

    Thank you. But using this value would need a huge amount of memory. Infact, I'm studying Au as a dopant on a structure with B and N.
    Thanks again


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