mod_constants.t

Go to the documentation of this file.

!> Module for physical and numeric constants
module mod_constants
 
  implicit none
  public
 
  ! A very small real number (but above machine precision)
  double precision, parameter :: smalldouble = 1.d-12
 
  !> A very large real number
  double precision, parameter :: bigdouble = 1.d+99
 
  !> some frequently used numbers
  double precision, parameter :: zero    = 0.0d0
  double precision, parameter :: one     = 1.0d0
  double precision, parameter :: two     = 2.0d0
  double precision, parameter :: half    = 0.5d0
  double precision, parameter :: quarter = 0.25d0
  double precision, parameter :: third   = 1.d0/3.0d0
 
  !> Pi
  double precision, parameter :: dpi=3.141592653589793238462643383279502884197169399375105d0
 
  !> Proton mass in cgs
  double precision, parameter :: mp_cgs = 1.672621777d-24 ! g
 
  !> Hydrogen mass in cgs
  double precision, parameter :: mh_cgs = 1.6733d-24 ! g
 
  !> Boltzmann constant in cgs
  double precision, parameter :: kb_cgs = 1.3806488d-16 ! erg K^-1
 
  !> Stefan Boltzmann constant in cgs from (2 pi^5 kB^4)/(15 c^2 h^3)
  double precision, parameter :: sigma_sb_cgs = 5.670374419d-5 ! erg s^-1 cm^-2 K^-4
 
  !> electron Thomson scattering cross-section in cgs from (8 pi/3) [alfa_FS * h/(2 pi me c)]^2
  double precision, parameter :: sigma_te_cgs = 6.6524587051d-25  ! cm^2
 
  !> Stefan Boltzmann constant in SI (2 pi^5 kB^4)/(15 c^2 h^3)
  double precision, parameter :: sigma_sb_si  = 5.670374419d-8 ! W m^-2 K^-4
 
  !> electron Thomson scattering cross-section in SI from (8 pi/3) [alfa_FS * h/(2 pi me c)]^2
  double precision, parameter :: sigma_te_si = 6.6524587051d-29  ! m^2
 
  !> Proton mass in SI
  double precision, parameter :: mp_si = 1.672621777d-27 ! kg
 
  !> Boltzmann constant in SI
  double precision, parameter :: kb_si = 1.3806488d-23 ! J K^-1
 
  !> Permeability in SI
  double precision, parameter :: miu0_si = 1.2566370614d-6 ! H m^-1
 
  !> Speed of light in SI
  double precision, parameter :: c_si = 2.99792458d8 ! m s^-1
 
  !> universal constants as specified in cgs units
  double precision, PARAMETER :: const_c     = 2.99792458d10   ! cm s^-1           ; Speed of light
  double precision, PARAMETER :: const_me    = 9.1093897d-28   ! g                 ; Electron mass
  double precision, PARAMETER :: const_mp    = 1.672621777d-24 ! g                 ; Proton mass
  double precision, PARAMETER :: const_e     = 4.8032068d-10   ! g^1/2 cm^3/2 s^-1 ; Electron charge
  double precision, PARAMETER :: const_lsun  = 3.828d33        ! erg s^-1          ; Solar luminosity
  double precision, PARAMETER :: const_msun  = 1.98892d33      ! g                 ; Solar mass
  double precision, PARAMETER :: const_rsun  = 6.9570d10       ! cm                ; Solar radius
  double precision, PARAMETER :: const_kb    = 1.3806488d-16   ! erg K^-1          ; Boltzmann constant
  double precision, PARAMETER :: const_h     = 6.6260755d-27   ! erg s             ; Planck constant
  double precision, PARAMETER :: const_pc    = 3.08567758128d18! cm                ; 1 parsec
  double precision, PARAMETER :: const_g     = 6.67191d-8      ! cm^3 g^-1 s^-2    ; Cavendish gravitational constant
  double precision, PARAMETER :: const_sigma = 5.670367d-5     ! erg cm^-2 K^-4 s^-1 ; Stefan-Boltzman constant
 
  ! Conversion factors:
  double precision, PARAMETER :: const_ev    = 1.6021772d-12   ! erg/eV            ; Electron volt
  double precision, PARAMETER :: const_tera  = 1.d12           ! -                 ; Tera
  double precision, PARAMETER :: const_peta  = 1.d15           ! -                 ; Peta
  double precision, PARAMETER :: const_years = 3.1536d7        ! s year^-1         ; seconds in a year
 
  !> A very large integer
  integer, parameter :: biginteger = 10000000
 
end module mod_constants