CCL: Core ionization potential calculation in VASP

 Sent to CCL by: Michael Sluydts [michael.sluydts()ugent.be]
Maybe as an addendum, if you do try VASP for this you should use a large enough box ( such as 20 by 20.5 by 21 to induce some assymetry). It's also recommended to set the spin of the system using NUPDOWN (or MAGMOM) and keep an eye on the occupation of the energy levels in the OUTCAR (k-point no 1 etc).
Note that this strategy is valid for cations. For anions the extra electrons will have a very long tail in charge density (possibly requiring large boxes) and converge badly. 
 Best regards,
 Michael Sluydts
 /Haya Kornweitz - Dr' hayak---ariel.ac.il schreef op 9/11/2014 11:30:
 
 Sent to CCL by:
 =?windows-1255?B?5+nkIPfl+PDl5en1IC0g4/gvSGF5YSBLb3Jud2VpdHogLSBEcic=?=
 	[hayak^ariel.ac.il]
 Ionization energy is defined for an atom/molecule in vacumm, so you have to take
 a single atom/molecule in your POSCAR, calculate it's energy and then repit the
 calculation writeing
 NELECT =n-1 in the INCAR.
 n - total No. of electrons.
 The difference of the energies is the ionization energy by definition.
 It is possible, but I am not sure that VASP is the best program to calculate
 Ionization energy.
 Haya
 -----Original Message-----
 
 From: owner-chemistry+hayak==ariel.ac.il*o*ccl.net [mailto:owner-chemistry+hayak==ariel.ac.il*o*ccl.net] On Behalf Of Shawkat
 Islam shawkatewu++gmail.com
 
 Sent: Sunday, November 09, 2014 2:49 AM
 To: חיה
 קורנוויץ - דר/Haya
 Kornweitz - Dr'
 Subject: CCL: Core ionizzation potential calculation in VASP
 Sent to CCL by: "Shawkat  Islam" [shawkatewu:gmail.com] Dear CCL
 users,
 I am a new VASP user.
 I want to calculate core ioniztion potential. Is it possible to calculate in
 VASP. If yes, could you please guide me how to do so? What changes should I have
 to make in the INCAR and POSCAR?
 Thanks.
 Shawkat
 Australia
 sislam|swin.edu.auhttp://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp-:-//www.ccl.net/chemistry/sub_unsub.shtmlhttp-:-//www.ccl.net/spammers.txt>;