#define m 9.10938291e-28
#define c 299792.458e5
#define mc (m*c)
#define mc2 (m*c*c)
#define e 4.80320451e-10
#define eV 1.602177e-12
#define AU 1.49599e13
#define sfu 1e-19
#define kB 1.3806488e-16
#define hPl 6.6261e-27
#define ieH (13.59844*eV)

double Saha(double n0, double T0);