namespace forcefields::unit_system

Overview

Physical constants and unit conversion. More…

namespace unit_system {
 
// global variables
 
const double R_gas = 8.314472;
const double k_boltzmann = 1.3806505e-23;
const double Na_avogadro = 6.0221415e23;
const double calory = 4.1868;
const double e_charge = 1.60217653e-19;
const double debye =     3.33564e-30;
const double one_over_4_pi_epsilon0 =     8.98755178495272255e+09;
const double sqrt_one_over_4_pi_epsilon0 = 9.48026992492973368e+04;
const double pi = 3.14159265358979312;
const double MOL = Na_avogadro;
const double DEGREE = pi / 180;
const char LENGTH[] = “A”;
const char TIME[] = “fs”;
const char MASS[] = “eV A^-2 fs^2”;
const char CURRENT[] = “e/fs”;
const char VELOCITY[] = “A fs^-1”;
const char ACCELERATION[] = “A fs^-2”;
const char FORCE[] = “eV/A”;
const char ENERGY[] = “eV”;
const char PRESSURE[] = “eV A^-3”;
const char CHARGE[] = “(eV A)^(-1/2)”;
const double METRE = 1e10;
const double KG = 1e10 / e_charge;
const double SECOND = 1e15;
const double AMPERE = 1e-15 / e_charge;
const char*const TEMPERATURE = ENERGY;
const double METRE_PER_SECOND = METRE / SECOND;
const double METRE_PER_SECOND2 = METRE_PER_SECOND / SECOND;
const double NEWTON = KG* METRE_PER_SECOND2;
const double JOULE = NEWTON* METRE;
const double COULOMB = AMPERE* SECOND;
const double WATT = JOULE / SECOND;
const double VOLT = WATT / AMPERE;
const double KELVIN = k_boltzmann* JOULE;
const double KILO = 1e3;
const double NANO = 1e-9;
const double FEMTO = 1e-15;
const double NM = NANO* METRE;
const double GRAM = KG / KILO;
const double GRAM_PER_MOL = GRAM / MOL;
const double G_PER_MOL = GRAM_PER_MOL;
const double KJ_PER_MOL = KILO* JOULE / MOL;
const double KJ = KILO* JOULE;
const double FS = FEMTO* SECOND;
const double ANGSTROM = 1e-10* METRE;
const double ANGSTROM2 = ANGSTROM* ANGSTROM;
const double ANGSTROM3 = ANGSTROM* ANGSTROM* ANGSTROM;
const double ECHARGE = e_charge* COULOMB;
const double EV = ECHARGE* VOLT;
const double CALORY = calory* JOULE;
const double KCAL_PER_MOL = KILO* CALORY / MOL;
const double BOHR = 5.291772108e-11* METRE;
const double HARTREE = 4.35974417e-18* JOULE;
const double ERGS = 1e-7* JOULE;
const double ONE_OVER_4_PI_EPSILON0 =     one_over_4_pi_epsilon0* METRE* JOULE / COULOMB / COULOMB;
 
} // namespace unit_system

Detailed Documentation

Physical constants and unit conversion.

Global Variables

const double one_over_4_pi_epsilon0 =     8.98755178495272255e+09

This is the quantity 1/(4*pi*epsilon0) in SI units.

const double sqrt_one_over_4_pi_epsilon0 = 9.48026992492973368e+04

This is the quantity 1/sqrt(4*pi*epsilon0) in SI units.