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【求助】alpha+bet 是什么意思？
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OUTCAR里的 E-fermi : 7.4279 XC(G=0): -13.2605 alpha+bet :-12.7584 除了fermi 能级外后面两个是什么意思？ |
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6楼2009-09-20 10:55:56
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fegg7502(金币+3,VIP+0):thank you very much! 9-20 16:38
fegg7502(金币+3,VIP+0):thank you very much! 9-20 16:38
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vasp论坛上的转贴 The fermi level (and the eigenvalues) are calculated based on a potential that does not include the G=0 component of the pseudopotential or the G=0 component of the coulombic potential (which is ill defined anyway). The term XC(G=0) is the G=0 component of the exchange-correlation potential. The alpha part of Alpha+bet is the G=0 term of the pseudopotential * (ZVAL/NELECT) where ZVAL is the total valance of the ions and NELECT is the total number of electrons (equal in a neutral cell). I have no idea what the beta part of Alpha+bet is. In my opinion, Alpha+bet is useless for calculating the work function or correcting the eigenvalues to be relative to vacuum. The best way to do this for a slab calculation is to use IDIPOL=3 and LDIPOL=.TRUE. (if the surface is normal to the z direction). This will correct for any dipole interactions between neighboring slabs and will also give you the vacuum potential on both sides of the slab. Just subtract the vacuum potential for the side of the slab that represents the actual surface from the fermi level to get the work function if your vacuum size is thick enough, the potential should level off to a constant value in the center of the vacuum. Please use the LVTOT=True input parameter and use the tool vtotav.f (with the LOCPOT file) to get the "zero" vacuum potential. The Fermi level should be taken as difference between the calculated fermi energy and this vacuum level then. http://cms.mpi.univie.ac.at/vasp-forum/forum_viewtopic.php?4.1609 这一句 The Fermi level should be taken as difference between the calculated fermi energy and this vacuum level then. 我就不明白了， difference between the calculated fermi energy and this vacuum level 应该是功函数才对啊，怎么说是费米能级，各位有什么高见阿 |
2楼2009-09-18 09:30:41
veryman
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3楼2009-09-18 09:52:58
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fegg7502(金币+2,VIP+0):thank you very much! 9-20 16:39
fegg7502(金币+2,VIP+0):thank you very much! 9-20 16:39
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真空能级减去费米能级的却是功函数 这也是vasp的班主说的 the work function Phi will then be evaluated from Phi = V(vacuum) - E_fermi with V(vacuum) ... potential in the center of the vacuum of the slab E_fermi ... Ferni level (given in OUTCAR). please be aware that the vacuum should be large enough to guarantee that the potential has reached its _constant_ vacuum level. http://cms.mpi.univie.ac.at/vasp-forum/forum_viewtopic.php?4.32 我搞不懂他所说的修正是怎么一回事？ |
4楼2009-09-18 20:31:48
