Dear All, I have optimized the structure for anatase simple tetragonal. The optimiized lattice parameters are a= 3.754336A. c=9.193631522694A. but the experimental values are a= 3.785A, c=9.514A. There is big difference in c value for optimised strucutre.But the same calculation for GGA pseudo potential gives the lattice parameter values which are good with experimental values. In literature previous results for LDA has good lattice parameter values. Which parameter I have to change in order to get good results for LDA? Below is my input and the version i have used is 5.2.1
&CONTROL title = 'anatase' , calculation = 'vc-relax' , restart_mode = 'from_scratch' , pseudo_dir = '/home/suresh/GN2/', outdir ='/home/suresh/Desktop/ashahicheck/asahiopt/tmp/', prefix = 'anatase' , tstress = .true. , tprnfor = .true. , / &SYSTEM ibrav = 6, A = 3.692, C = 9.471 , nat = 12, ntyp = 2, ecutwfc = 60 , exxdiv_treatment = 'none' , / &ELECTRONS / &IONS ion_dynamics = 'bfgs' , / &CELL cell_dynamics = 'bfgs' , / ATOMIC_SPECIES Ti 47.86700 Ti.pz-mt_fhi.UPF O 15.99940 O.pz-mt_fhi.UPF ATOMIC_POSITIONS (crystal) Ti 0.0000000 0.0000000 0.0000000 Ti 0.5000000 0.0000000 0.7500000 Ti 0.0000000 0.5000000 0.2500000 Ti 0.5000000 0.5000000 0.5000000 O 0.0000000 0.0000000 0.2066000 O 0.5000000 0.0000000 0.5434000 O 0.0000000 0.5000000 0.4566000 O 0.5000000 0.0000000 0.9566000 O 0.0000000 0.5000000 0.0434000 O 0.0000000 0.0000000 0.7934000 O 0.5000000 0.5000000 0.7066000 O 0.5000000 0.5000000 0.2934000 K_POINTS automatic 4 4 2 1 1 1 Thanks in advance. With Regards, A.Suresh, Research Scholar, Madurai Kamaraj University, Madurai.
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