Dear Yu Hailin The scf calculation which precedes the phonon calculation is likely poorly converged or the atoms are far from their equilibrium positions. HTH
Giuseppe On Friday, January 09, 2015 02:20:59 PM äºæµ·æ wrote: > The input file and resuts as shown follow: > > input file: > GaN G point phonon > &inputph > tr2_ph=1.0d-14, > prefix='GaN', > epsil=.true., > amass(1)=14.0037, > amass(2)=69.723, > outdir='./tempdir/', > fildyn='GaN.dynG', > / > 0.0 0.0 0.0 > > > The results: > > > ************************************************************************** > freq ( 1) = -37.374010 [THz] = -1246.662771 [cm-1] > freq ( 2) = -37.097882 [THz] = -1237.452154 [cm-1] > freq ( 3) = -36.243849 [THz] = -1208.964660 [cm-1] > freq ( 4) = -27.145266 [THz] = -905.468612 [cm-1] > freq ( 5) = -6.773759 [THz] = -225.948270 [cm-1] > freq ( 6) = -0.510448 [THz] = -17.026703 [cm-1] > freq ( 7) = 0.368416 [THz] = 12.289036 [cm-1] > freq ( 8) = 0.600643 [THz] = 20.035301 [cm-1] > freq ( 9) = 4.488708 [THz] = 149.727175 [cm-1] > freq ( 10) = 25.963394 [THz] = 866.045613 [cm-1] > freq ( 11) = 89.714931 [THz] = 2992.567990 [cm-1] > freq ( 12) = 91.148214 [THz] = 3040.377161 [cm-1] > ************************************************************************** > > > > > > > > > > > > At 2015-01-09 14:17:44, "äºæµ·æ" <[email protected]> wrote: > > Dear all, > > > I have calculated the phonon of GaN at G point. The input file and the results as shown follow. But the phonon results is obviously inaccuracy. How > to improve the precision of phonon calculation? Thanks in advance. > > > Best Regard! > > > Yu Hailin > > > College of Physics & Electronic Enginerring, > Changshu Institute of Technology > China ******************************************************** - Article premier - Les hommes naissent et demeurent libres et ègaux en droits. Les distinctions sociales ne peuvent être fondèes que sur l'utilitè commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la libertè, la propriètè, la sùretè et la rèsistance à l'oppression. ******************************************************** Giuseppe Mattioli CNR - ISTITUTO DI STRUTTURA DELLA MATERIA v. Salaria Km 29,300 - C.P. 10 I 00015 - Monterotondo Stazione (RM) Tel + 39 06 90672836 - Fax +39 06 90672316 E-mail: <[email protected]> http://www.ism.cnr.it/english/staff/mattiolig ResearcherID: F-6308-2012
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