Class nucmass_semi_empirical (o2scl)¶
-
class nucmass_semi_empirical : public o2scl::nucmass_fit_base¶
Semi-empirical mass formula.
A simple semi-empirical mass formula of the form
\[ E/A = B + S_s \frac{1}{A^{1/3}}+E_c \frac{Z^2}{A^{4/3}} + S_v \left(1-\frac{2Z}{A}\right)^2+E_{\mathrm{pair}}(Z,N) \]where the pairing energy is given by\[ E_{\mathrm{pair}}(Z,N) = - \frac{E_{\mathrm{pair}}}{2 A^{3/2}} \left[ \cos \left( \pi Z \right)+\cos \left( \pi N \right) \right] \]which is equivalent to the traditional prescription\[\begin{split} E_{\mathrm{pair}}(Z,N) = \frac{E_{\mathrm{pair}}}{A^{3/2}} \times \left\{ \begin{array}{rl} -1 & \mathrm{N~and~Z~even} \\ +1 & \mathrm{N~and~Z~odd} \\ 0 & \mathrm{otherwise} \end{array} \right. \end{split}\]when \( Z \) and \( N \) and integers.There is an example of the usage of this class given in the Nuclear mass fit example.
Note
The default parameters are arbitrary, and are not determined from a fit.
Public Types
-
typedef boost::numeric::ublas::vector<double> ubvector¶
Public Functions
-
inline virtual const char *type()¶
Return the type,
"nucmass_semi_empirical".
-
nucmass_semi_empirical()¶
-
virtual double mass_excess_d(double Z, double N)¶
Given
ZandN, return the mass excess in MeV.
-
inline virtual double mass_excess(int Z, int N)¶
Given
ZandN, return the mass excess in MeV.
-
typedef boost::numeric::ublas::vector<double> ubvector¶