Fit Function: h_hin_janev

Fit Function \[\sigma_{ion}^{n=1}(E)= 10^{-16}A_1 \Bigg[\frac{e^{\frac{-A_2}{E}} \ln(1+A_3E)}{E} + \frac{A_4e^{-A_5E}}{E^{A_6} + A_7E^{A_8}}\Bigg]\]
Comments Python code requires NumPy imported as `np`.

Python

Arguments
namedescriptionunitstype(s)
E impact energy keV u-1 float, np.ndarray
A1 fit coefficient keV cm2 u-1 float
A2 fit coefficient keV u-1 float
A3 fit coefficient keV-1 u float
A4 fit coefficient undef float
A5 fit coefficient float
A6 fit coefficient float
A7 fit coefficient undef float
A8 fit coefficient float
Return values
namedescriptionunitstype(s)
sigma cross section cm2 float, np.ndarray
Code 
def h_hin_janev(E, A1, A2, A3, A4, A5, A6, A7, A8):
    """
    This function calculatesproton impact ionization cross sections (in cm2) of 
    H n=1.
    param E: requested proton-impact energy in keV
    type E: float, np.ndarray
    param Ai: fit coefficient 
    type Ai: float
    """
    sigma = 1e-16*A1*(np.exp(-A2/E)*np.log(1+A3*E)/E + 
                    A4*np.exp(-A5*E)/(E**A6+A7*E**A8))
    return sigma