mirror of https://gitlab.com/QEF/q-e.git
90 lines
3.5 KiB
Fortran
90 lines
3.5 KiB
Fortran
!
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! Copyright (C) 2002-2003 FPMD & PWSCF 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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MODULE constants
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!----------------------------------------------------------------------------
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!
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USE kinds
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!
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! ... The constants needed everywhere
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!
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IMPLICIT NONE
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!
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SAVE
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!
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REAL(dbl) :: PI, tpi, FPI
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REAL(dbl) :: SQRTPI, SQRTPM1, sqrt2
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!
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! ... Physical constants
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!
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REAL(dbl), PARAMETER :: K_BOLTZMAN_SI = 1.38066D-23 ! J K^-1
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REAL(dbl), PARAMETER :: K_BOLTZMAN_AU = 3.1667D-6 ! Hartree K^-1
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REAL(dbl), PARAMETER :: K_BOLTZMAN_M1_AU = 315795.26D0 ! Hartree^-1 K
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REAL(dbl), PARAMETER :: FACTEM = 315795.26D0 ! 27.212d0*11605.d0 Hartree^-1 K
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!
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! ... Physical constants defining the Atomic Units System
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!
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REAL(dbl), PARAMETER :: BOHR_RADIUS_SI = 0.529177D-10 ! m
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REAL(dbl), PARAMETER :: BOHR_RADIUS_CM = 0.529177D-8 ! cm
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REAL(dbl), PARAMETER :: BOHR_RADIUS_ANGS = 0.529177D0 ! angstrom
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REAL(dbl), PARAMETER :: ELECTRONMASS_SI = 9.10953D-31 ! Kg
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REAL(dbl), PARAMETER :: ELECTRONMASS_UMA = 5.4858D-4 ! uma
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!
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! ... Units conversion factors
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!
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REAL(dbl), PARAMETER :: ELECTRONVOLT_SI = 1.6021892D-19 ! J
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REAL(dbl), PARAMETER :: UMA_SI = 1.66057D-27 ! Kg
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REAL(dbl), PARAMETER :: ANGSTROM_AU = 1.889727D0 ! au
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REAL(dbl), PARAMETER :: AU_TO_OHMCMM1 = 46000.0D0 ! (ohm cm)^-1
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REAL(dbl), PARAMETER :: AU_KB = 294210.0D0 ! Kbar
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REAL(dbl), PARAMETER :: KB_AU = 1.0D0/294210.0D0 ! au
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REAL(dbl), PARAMETER :: AU = 27.212D0 ! eV
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REAL(dbl), PARAMETER :: RY = 13.606D0 ! eV
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! REAL(dbl), PARAMETER :: AU = 27.211652D0 ! eV
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! REAL(dbl), PARAMETER :: RY = 13.605826D0 ! eV
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REAL(dbl), PARAMETER :: SCMASS = 1822.89D0 ! uma to au ( mass of a proton )
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REAL(dbl), PARAMETER :: UMA_AU = 1822.89D0 ! au
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REAL(dbl), PARAMETER :: AU_TERAHERTZ = 2.418D-5 ! THz
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REAL(dbl), PARAMETER :: TERAHERTZ = 2.418D-5 ! from au to THz
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REAL(dbl), PARAMETER :: AU_SEC = 2.4189D-17 ! sec
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!
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!
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PARAMETER( pi = 3.14159265358979323846_dbl )
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PARAMETER( tpi = 2.0_dbl * 3.14159265358979323846_dbl )
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PARAMETER( fpi = 4.0_dbl * 3.14159265358979323846_dbl )
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PARAMETER( sqrtpi = 1.77245385090551602729_dbl )
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PARAMETER( sqrtpm1 = 1.0_dbl / sqrtpi )
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PARAMETER( sqrt2 = 1.41421356237309504880 )
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!
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!
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REAL(dbl), PARAMETER :: rhothr = 1.0e-5_dbl ! tolerance
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REAL(dbl), PARAMETER :: gsmall = 1.0d-12
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!
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REAL(dbl), PARAMETER :: e2 = 2.D0 ! the square of the electron charge
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REAL(dbl), PARAMETER :: degspin = 2.D0 ! the number of spins per level
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REAL(dbl), PARAMETER :: rytoev=13.6058d0 ! conversion from Ry to eV
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!
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! ... mass conversion: a.m.u to a.u. (Ry)
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!
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REAL(dbl), PARAMETER :: amconv= 1.66042d-24/9.1095d-28*0.5d0
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!
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! ... pressure conversion from Ry/(a.u)^3 to K
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!
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REAL(dbl), PARAMETER :: uakbar= 147105.d0
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!
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! ... zero up to a given accuracy
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!
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REAL(dbl), PARAMETER :: eps4 = 1.0D-4
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REAL(dbl), PARAMETER :: eps8 = 1.0D-8
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REAL(dbl), PARAMETER :: eps16 = 1.0D-16
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REAL(dbl), PARAMETER :: eps32 = 1.0D-32
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!
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REAL(dbl), PARAMETER :: eV_to_kelvin = 1.1604D4 ! from eV to Kelvin
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!
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END MODULE constants
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