15 double cs, cs21 , cs31 , cs32;
16 double a21 , a31 , a32;
double atom_pop3(double g1, double g2, double g3, double o12, double o13, double o23, double a21, double a31, double a32, double Tex12, double Tex23, realnum *pop2, double abund, double gam2, double r12, double r13)