Dear Dr. Iurii Timrov, Thanks for the reply. "The two codes (Lanczos and Davidson) must give you the same absorption spectrum (when both are converged)."
How to check the convergence for both the codes ?? I was checking the optical absorption spectra for CH4 molecule (using the given example for the TDDFPT package) using both the code. They are not matching with each other. Also I was trying to do for Carbon-dimer. In this case also, the spectrum using both the codes are not matching with each other. The input files are given below. I have checked the ecut & ecutfock convergence and also relaxed the structure. *For turbo_davidson.x ::* *PW.X:*&CONTROL calculation = "scf", restart_mode = "from_scratch" prefix = "C2", pseudo_dir = "../pseudo/", outdir = "./tmp/", / &SYSTEM ibrav = 0, nat = 2, ntyp = 1, ecutwfc = 75, ecutfock = 75, nosym = .true., input_dft = 'PBE0', x_gamma_extrapolation = .false., exxdiv_treatment = 'vcut_spherical', / &ELECTRONS conv_thr = 1.D-10, mixing_beta = 0.6, adaptive_thr = .true., / CELL_PARAMETERS angstrom 10.0 0.0 0.0 0.0 10.0 0.0 0.0 0.0 10.0 ATOMIC_SPECIES C 12.01 C.pbe-mt_gipaw.UPF ATOMIC_POSITIONS (angstrom) C 1.248029552 0.000000000 0.000000000 C 0.000000000 0.000000000 0.000000000 K_POINTS {Gamma} *Turbo_davidson.x:*&lr_input prefix="C2", outdir="./tmp/", / &lr_dav ecutfock = 75, num_eign=30, num_init=60, num_basis_max = 300, residue_conv_thr = 1.0E-4, start = 0.0 finish = 1.0, step = 0.0005, broadening = 0.005, reference = 0.0, d0psi_rs = .true., lshift_d0psi = .true., p_nbnd_virt = 20 / *For turbo_lanczos.x ::* I used the same file for pw.x as given above. *Turbo_lanczos.x:*&lr_input prefix="C2", outdir="./tmp/", restart_step=500, / &lr_control itermax=2000, ipol=4, ecutfock = 75, pseudo_hermitian = .true., d0psi_rs = .true., / *Turbo_spectrum.x:*&lr_input prefix='C2', outdir="./tmp/", itermax0 = 410 itermax = 10000 epsil=0.01 start=0.0d0 end=1.50d0 increment=0.001d0 ipol=4 / Thanks & regards, Prem Sen Ph.D. Student, IIT Bombay *,* Mumbai,India *.*
_______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum