(* Fundamental dimensionless constants in SI units *)
BoltzmannConstant=1.3806503 10^(-23) kg m^2/s^2/Kelvin;
SpeedOfLight= 2.99792458 10^8 m/s; c=SpeedOfLight;
PlanckConstant = 1.05457148 10^(-34) kg m^2/s; hbar=PlanckConstant;
ElectronCharge=1.60217646 10^(-19) Coulomb;

(* Some dimensionless numbers within SI *)
FineStructureConstant = 1/137.035999;
AvogadroNumber = 6.022 10^(23);

(* Defining the SI Ampere *)
Ampere = Coulomb/s;

(* The energy unit eV *)
Joule = kg m^2/s^2;
Volt=Joule/Coulomb;
eV = ElectronCharge Volt;
Print["eV = ", eV]