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chuckv |
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!---------------------------------------------------------------------------- |
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! Module Constants |
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! |
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!---------------------------------------------------------------------------- |
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! Module supplies various constants to simulation. |
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! |
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! . Mathematical constants: |
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! PI Value for pi from atan |
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! . Defined Physical constants: |
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! |
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! amu_to_kg a.m.u. to kg |
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! atm_to_pascals Atmospheres to pascals |
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! ev_to_kj electron volts to kJ/mol |
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! k_boltz Boltzmans constant |
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! kcal_to_kj kcal/mol to kJ/mol |
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! navogadro Avogadro's number |
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! |
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! . Derived Physical constants: |
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! |
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! R Gas constant |
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! TO_DEGREES Converts radians to degrees |
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! TO_HZ cm^-1 to fs^-1 |
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! TO_RADIANS Degrees to radians |
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! TO_WAVENUMBERS To cm^-1 |
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! |
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! . Constants used for simulation |
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! |
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! amua2fs2_to_K From amu (A fs^-1)^2 to Kelvin |
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! amua3fs2_to_kjmol From amu (A fs^-1)^2 to kJ/mol |
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! ms_to_afs From m/s to A/fs |
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! kJmol_to_amua2fs2 From kJ/mol to amu (A/fs)^2 |
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! amua2fs2_to_kcalmol From amu (A fs^-1)^2 to kcal/mol |
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! kcalmol_to_amua2fs2 From Kcal/mol to amu (A/fs)^2 |
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! . Notes |
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! Fundamental units for this simulations are |
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! time: femtoseconds |
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! distance: angstroms |
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! energy: kcal/mol |
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! temperature: Kelvin |
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!--------------------------------------------------------------------------------- |
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module constants |
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use definitions, ONLY : DP |
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implicit none |
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public |
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!-------------------------------------------------------------------------------- |
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! . Mathematical and Physical constants |
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!-------------------------------------------------------------------------------- |
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! . Atomic mass units to Kg. |
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real( kind = DP ), parameter :: amu_to_kg = 1.6605402E-27_DP |
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! . Atmospheres to Pascals. |
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REAL ( KIND = DP ), PARAMETER :: ATM_TO_PASCALS = 1.013250E+5_DP |
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! . The conversion factor from atomic units to Debyes. |
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REAL ( KIND = DP ), PARAMETER :: AU_TO_DB = 2.54176568_DP |
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! . The conversion factor from atomic units to electron-volts. |
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REAL ( KIND = DP ), PARAMETER :: AU_TO_EV = 27.21_DP |
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! . The conversion factor from atomic units to kJ/mole. |
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REAL ( KIND = DP ), PARAMETER :: AU_TO_KJ = 27.21_DP * 4.184_DP * 23.061_DP |
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! . The conversion factor from Bohrs to Angstroms. |
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REAL ( KIND = DP ), PARAMETER :: BOHRS_TO_ANGSTROMS = 0.529177249_DP |
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! . The speed of light. |
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REAL ( KIND = DP ), PARAMETER :: C = 299792458.0_DP |
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! . The conversion factor from electron-volts to kJ/mole. |
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REAL ( KIND = DP ), PARAMETER :: EV_TO_KJ = 4.184_DP * 23.061_DP |
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! . The permittivity of the vacuum (F m^-1). |
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REAL ( KIND = DP ), PARAMETER :: E0 = 8.854187817E-12_DP |
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! . Boltzmann's constant. |
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REAL ( KIND = DP ), PARAMETER :: K_BOLTZ = 1.380658E-23_DP |
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! . kcal mol^-1 to kJ mol^-1. |
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REAL ( KIND = DP ), PARAMETER :: KCAL_TO_KJ = 4.184_DP |
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! . Avogadro's number. |
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REAL ( KIND = DP ), PARAMETER :: NAVOGADRO = 6.0221367E+23_DP |
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! . Pi. Calculated to machine precision |
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REAL ( KIND = DP ), PARAMETER :: PI = 3.141592653589793_DP |
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!REAL ( KIND = DP ) :: pi_tmp = 4.0_DP*atan(1.0_DP) |
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!REAL ( KIND = DP ), PARAMETER :: PI = pi_tmp |
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REAL ( KIND = DP ), PARAMETER :: TWOPI = 2.0E0_DP * PI |
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! . Planck's constant. |
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REAL ( KIND = DP ), PARAMETER :: PLANCK = 6.6260755E-34_DP |
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! . Elementary charge in coulombs. |
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REAL ( KIND = DP ), PARAMETER :: TO_COULOMBS = 1.60217733E-19_DP |
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!----------------------------------------------------------------------------------- |
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! . Derived constants |
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!----------------------------------------------------------------------------------- |
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! . The conversion factor from Angstroms to Bohrs. |
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REAL ( KIND = DP ), PARAMETER :: ANGSTROMS_TO_BOHRS = 1.0_DP / BOHRS_TO_ANGSTROMS |
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! . The conversion factor from e^2/Angstroms to kJ mol^-1. |
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REAL ( KIND = DP ), PARAMETER :: ELECT_CONST = ( 1.0E+7_DP * NAVOGADRO * TO_COULOMBS**2 ) / ( 4.0_DP * PI * E0 ) |
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! . The conversion factor from atm. Angstroms^3 to kJ mol^-1. |
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REAL ( KIND = DP ), PARAMETER :: PV_TO_KJ_MOLE = ATM_TO_PASCALS * NAVOGADRO * 1.0E-33_DP |
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! . The gas constant (kJ mol^-1 K^-1). |
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REAL ( KIND = DP ), PARAMETER :: R = K_BOLTZ * NAVOGADRO * 1.0E-3_DP |
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! . The conversion factor from cm^-1 to ps^-1. |
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REAL ( KIND = DP ), PARAMETER :: TO_HZ = C / 1.0E+10_DP |
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! . Radians to degrees. |
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REAL ( KIND = DP ), PARAMETER :: TO_DEGREES = 180.0_DP / PI |
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! . The conversion factor from internal units to km/mole. |
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REAL ( KIND = DP ), PARAMETER :: TO_KM_PER_MOLE = ( NAVOGADRO * TO_COULOMBS**2 ) / ( 12.0_DP * 1.0E+3_DP * E0 * C**2 * AMU_TO_KG ) |
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! . Degrees to radians. |
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REAL ( KIND = DP ), PARAMETER :: TO_RADIANS = PI / 180.0_DP |
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! . The conversion factor from internal units to cm^-1. |
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REAL ( KIND = DP ), PARAMETER :: TO_WAVENUMBERS = 1.0E+11_DP / ( 2.0_DP * PI * C ) |
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!-------------------------------------------------------------------------------------------- |
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! . Simulation constants |
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! . The conversion factor from amu A^2 fs^-2 to kJ mol^-1 (equivalent to |
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! . AMU_TO_KG * NAVOGADRO * 10^-3 / MS_TO_AFS^2 ). |
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REAL ( KIND = DP ), PARAMETER :: AMUA2FS2_TO_KJMOL = 1.0E+4_DP |
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! . The conversion factor from m s^-1 to A fs^-1. |
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REAL ( KIND = DP ), PARAMETER :: MS_TO_AFS = 1.0E-5_DP |
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! . The conversion factor from amu A^2 fs^-2 to Kelvin. |
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REAL ( KIND = DP ), PARAMETER :: AMUA2FS2_TO_K = AMU_TO_KG / ( K_BOLTZ * MS_TO_AFS**2 ) |
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! . The conversion factor from kJ mol^-1 to amu A^2 fs^-2. |
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REAL ( KIND = DP ), PARAMETER :: KJMOL_TO_AMUA2FS2 = 1.0_DP / AMUA2FS2_TO_KJMOL |
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! . The conversion factor from amu A^2 fs to Kcal/mol |
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REAL( KIND = DP ), PARAMETER :: AMUA2FS2_TO_KCALMOL = AMUA2FS2_TO_KJMOL/KCAL_TO_KJ |
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! . The conversion factor from kcal mol^-1 to amu A^2 fs^-2. |
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REAL ( KIND = DP ), PARAMETER :: KCALMOL_TO_AMUA2FS2 = 1.0_DP / AMUA2FS2_TO_KCALMOL |
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end module constants |
