mirror of https://gitlab.com/QEF/q-e.git
147 lines
4.3 KiB
Fortran
147 lines
4.3 KiB
Fortran
!
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! Copyright (C) 2001-2009 Quantum ESPRESSO group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!-----------------------------------------------------------------------
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PROGRAM phonon
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!-----------------------------------------------------------------------
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!
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! ... This is the main driver of the phonon code.
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! ... It reads all the quantities calculated by pwscf, it
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! ... checks if some recover file is present and determines
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! ... which calculation needs to be done. Finally, it makes
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! ... a loop over the q points. At a generic q, if necessary it
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! ... recalculates the band structure calling pwscf again.
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! ... Then it can calculate the response to an atomic displacement,
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! ... the dynamical matrix at that q, and the electron-phonon
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! ... interaction at that q. At q=0 it can calculate the linear response
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! ... to an electric field perturbation and hence the dielectric
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! ... constant, the Born effective charges and the polarizability
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! ... at imaginary frequencies.
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! ... At q=0, from the second order response to an electric field,
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! ... it can calculate also the electro-optic and the raman tensors.
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! ... Presently implemented:
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! ... dynamical matrix (q/=0) NC [4], US [4], PAW [4]
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! ... dynamical matrix (q=0) NC [5], US [5], PAW [4]
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! ... dielectric constant NC [5], US [5], PAW [3]
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! ... born effective charges NC [5], US [5], PAW [3]
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! ... polarizability (iu) NC [2], US [2]
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! ... elctron-phonon NC [3], US [3]
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! ... electro-optic NC [1]
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! ... raman tensor NC [1]
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!
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! NC = norm conserving pseudopotentials
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! US = ultrasoft pseudopotentials
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! PAW = projector augmented-wave
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! [1] LDA, [2] [1]+GGA, [3] [2]+LSDA/sGGA, [4] [3]+Spin-orbit/nonmagnetic,
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! [5] [4]+Spin-orbit/magnetic
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!
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USE io_global, ONLY : stdout
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USE disp, ONLY : nqs
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USE control_ph, ONLY : epsil, trans, elph, bands_computed
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USE output, ONLY : fildrho
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USE check_stop, ONLY : check_stop_init
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USE ph_restart, ONLY : ph_writefile, destroy_status_run
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USE save_ph, ONLY : clean_input_variables
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USE mp_global, ONLY: mp_startup, nimage
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USE image_io_routines, ONLY : io_image_start
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USE environment, ONLY: environment_start
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!
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IMPLICIT NONE
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!
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INTEGER :: iq
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LOGICAL :: do_band, do_iq, setup_pw
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CHARACTER (LEN=9) :: code = 'PHONON'
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CHARACTER (LEN=256) :: auxdyn
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!
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! Initialize MPI, clocks, print initial messages
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!
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#ifdef __PARA
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CALL mp_startup ( )
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IF (nimage>1) CALL io_image_start()
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#endif
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CALL environment_start ( code )
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!
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WRITE( stdout, '(/5x,"Ultrasoft (Vanderbilt) Pseudopotentials")' )
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!
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! ... and begin with the initialization part
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!
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CALL phq_readin()
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!
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CALL check_stop_init()
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!
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! ... Checking the status of the calculation and if necessary initialize
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! ... the q mesh
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!
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CALL check_initial_status(auxdyn)
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!
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DO iq = 1, nqs
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!
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CALL prepare_q(auxdyn, do_band, do_iq, setup_pw, iq)
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!
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! If this q is not done in this run, cycle
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!
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IF (.NOT.do_iq) CYCLE
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!
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! If necessary the bands are recalculated
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!
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IF (setup_pw) CALL run_pwscf(do_band)
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!
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! Initialize the quantities which do not depend on
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! the linear response of the system
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!
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CALL initialize_ph()
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!
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! electric field perturbation
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!
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IF (epsil) CALL phescf()
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!
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! phonon perturbation
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!
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IF ( trans ) THEN
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!
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CALL phqscf()
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CALL dynmatrix()
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!
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IF ( fildrho /= ' ' ) CALL punch_plot_ph()
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!
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END IF
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!
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! electron-phonon interaction
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!
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IF ( elph ) THEN
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!
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IF ( .NOT. trans ) THEN
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!
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CALL dvanqq()
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CALL elphon()
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!
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END IF
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!
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CALL elphsum()
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!
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END IF
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!
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! ... cleanup of the variables for the next q point
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!
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CALL clean_pw_ph(iq)
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!
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END DO
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CALL ph_writefile('init',0)
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CALL clean_input_variables()
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CALL collect_grid_files()
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CALL destroy_status_run()
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!
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IF (bands_computed) CALL print_clock_pw()
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!
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CALL stop_ph( .TRUE. )
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!
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STOP
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!
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END PROGRAM phonon
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