Dear Mengxi Wu

`If I clearly understand you, you are considering the GAMMA point where`

`the bands are degenerate.`

`At the GAMMA point these bands have the same symmetry to my point of`

`view, explaining why the dipole matrix is non-zero. Thus your result is`

`expected to my point of view.`

Best Regards Xavier Le 13/11/2016 à 17:29, Little Grass a écrit :

Dear WIEN2k users,I'm trying to study the dipole matrix elements of MgO at Gamma point,but the dipole matrix elements between the degenerated bands seem tohave been mixed together. Are there any ways to sort out thedegeneracy, so that the dipole matrix elements are non-zero only forbands with the same symmetry?The band structure can be generated from the spaghetti program. Inaddition, bands with different symmetries are colored differently withirrep. For example, Fig1 shows the band structure from X to Gamma toX. According to symmetry, only the bands with the same color will bedipole allowed in px. So we expect that the dipole matrix elements (infile mommat2) for px is zero between bands with different colors. Forexample, the dipole matrix elements between band 6 and band 9 isnon-zero, but the dipole matrix elements between band 7 and 9 or 8 and9 are zero. But if one looks at the px component of the dipole matrixelement from the optic program, we see that at Gamma point, the dipolematrix elements between the degenerated bands are mixed together. Forexample, dipole matrix elements between band 6 and 9, between 7 and 9,and between 8 and 9 are all non-zero. In other words, the dipolematrix is much denser than it should be.So is there a way to fix the dipole matrix so that the dipole matrixbecome very sparse and only bands with the same symmetry have non-zerodipole matrix elements?Fig1:http://imgur.com/a/c7p0u Thanks in advance for the help. Best, Mengxi Wu _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html

_______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html