Dear Raheleh In the case of degauss, you should use the smallest value at which your calculation does not struggle to converge. Try, e.g., 0.01 Ry. Look in the output at the smearing contribution to total energy
smearing contrib. (-TS) = 0.00081361 Ry and make some tests to ensure that your total energy values are quite unaffected by different smearing values. If your system is an insulator, you should face no particular problems. In the case of mixing beta, you can start with a quite high value, e.g., 0.5, in a davidson diagonalization scheme. If your scf calculation does not converge you could try to reduce the mixing value down to 0.1 or 0.05 (this will slow your calculation...) or to use the robust cg diagonalization scheme (this will slow very much your calculation...). Hope this helps Giuseppe On Saturday 08 May 2010 10:04:55 raheleh vaziri wrote: > Dear All, > > > ?I don't know?that my molecule is metal, insulator or semiconductor , thus, > what is suitable value for degauss and mixing_beta? > > thank you for any help > > Raheleh Vaziri. -- ******************************************************** - Article premier - Les hommes naissent et demeurent libres et ?gaux en droits. Les distinctions sociales ne peuvent ?tre fond?es que sur l'utilit? commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la libert?, la propri?t?, la s?ret? et la r?sistance ? l'oppression. ******************************************************** ? ?Giuseppe Mattioli ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?CNR - ISTITUTO DI STRUTTURA DELLA MATERIA ? ? ?v. Salaria Km 29,300 - C.P. 10 ? ? ? ? ? ? ? ? ? ?I 00016 - Monterotondo Stazione (RM) ? ? ? ? ? ? ?Tel + 39 06 90672836 - Fax +39 06 90672316 ? ? ? ?E-mail: <giuseppe.mattioli at ism.cnr.it>
