Dear All, I am trying to calculate Raman spectra of graphene nanoribbon. At the first step, I am trying to reproduce the result reported in Nature 2010, 466, 470-473 by J Cai et al.(DOI:10.1038/nature09211).
I found a tutorial documents and examples of MASTANI2014 on the internet . http://www.iiserpune.ac.in/~smr2626/talks-presentations.html At the 11th July session, Raman-IR example files are provided. On this calculation, Raman signal intensity were not consistent as reported results. Especially, a vibration mode at 1440 cm-1 shift gave a strong intensity. The example calculated using K points as below. K_POINTS AUTOMATIC 02 1 1 0 0 0 I also tried K points increased as below. K_POINTS AUTOMATIC 10 4 4 0 0 0 (Calculated on 54 points) However, The vibration mode of 1440 cm-1 shift is still too strong. I use Quantum Espresso (5.1.1 build on Linux). I already modify the source code of phq_setup.f90 in PHonon to calculate Raman using PBE-GGA pseudopotential. I cite input files of MASTANI-2014 examples, and teach me how to improve Raman intensity as same as reported simulation. Thanks in advance, Best regards, Takahiro Nakae, Ph.D Institute of Advanced Energy Kyoto University -gar-w_05-1H-pw.in &control calculation = 'scf' restart_mode = 'from_scratch' prefix = 'gar-w_05-1H' tstress = .false. tprnfor = .true. wf_collect = .true. verbosity = 'medium' pseudo_dir = '../PP_LIBRARY/' outdir = './scratch/' etot_conv_thr = 1e-6 forc_conv_thr = 1e-5 / &system ibrav = 8 a = 4.26084498661943814205 b = 13 c = 8 nat = 18 ntyp = 2 ecutwfc = 35 / occupations = 'smearing' smearing = 'fermi-dirac' degauss = 0.004 &electrons conv_thr = 1e-9 mixing_beta = 0.5 / &IONS trust_radius_ini = 0.01 bfgs_ndim = 3 pot_extrapolation = 'second_order' wfc_extrapolation = 'second_order' / ATOMIC_SPECIES C 12.0107 C.pbe-mt_gipaw.UPF H 1.0079 H.pbe-vbc.UPF ATOMIC_POSITIONS alat H 0.216359182 -1.091988780 -0.000000000 H 0.783640818 -1.091988780 -0.000000000 C 0.339700889 -0.867654128 -0.000000000 C 0.660299111 -0.867654128 -0.000000000 C 0.170554615 -0.580838126 -0.000000000 C 0.829445385 -0.580838126 -0.000000000 C 0.330967203 -0.293018014 0.000000000 C 0.669032797 -0.293018014 -0.000000000 C 0.165591369 0.000000000 0.000000000 C 0.834408631 -0.000000000 0.000000000 C 0.330967203 0.293018014 -0.000000000 C 0.669032797 0.293018014 0.000000000 C 0.170554615 0.580838126 0.000000000 C 0.829445385 0.580838126 -0.000000000 C 0.339700889 0.867654128 0.000000000 C 0.660299111 0.867654128 0.000000000 H 0.216359182 1.091988780 -0.000000000 H 0.783640818 1.091988780 -0.000000000 K_POINTS AUTOMATIC 02 1 1 0 0 0 -the end of file -gar-w_05-1H-ph.in phonons of Chevron-like ribbon at Gamma &inputph tr2_ph = 1e-12 prefix = 'gar-w_05-1H' amass(1) = 12.0107 amass(2) = 1.0079 outdir = './scratch/' fildyn = 'gar-w_05-1H-ph.dyn' recover = .false. epsil = .true. lraman = .true. trans = .true. fildrho = "gar-w_05-1H-ph.fildrho" max_seconds = 350000 / 0.0 0.0 0.0 -the end of file -gar-w_05-1H-dynmat.in &input fildyn = 'gar-w_05-1H-ph.dyn' filxsf = 'gar-w_05-1H-dynmat.axsf' filmol = 'gar-w_05-1H-dynmat.mold' filout = 'gar-w_05-1H-dynmat.dat' / -the end of file _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum