Fit Function: h_hcx_janev

Fit Function \[\sigma_{CX}^{n=1}(E)= \frac{10^{-16}A_1 \ln \big( \frac{A_2}{E} + A_6 \big)}{1 + A_3E + A_4E^{3.5} + A_5E^{5.4}}\]
Comments Python code requires NumPy imported as `np`.

Python

Arguments
namedescriptionunitstype(s)
E impact energy keV u-1 float, np.ndarray
A1 fit coefficient cm2 float
A2 fit coefficient keV u-1 float
A3 fit coefficient keV-1 u float
A4 fit coefficient undef float
A5 fit coefficient undef float
A6 fit coefficient float
Return values
namedescriptionunitstype(s)
sigma cross section cm2 float, np.ndarray
Code 
def h_hcx_janev(E, A1, A2, A3, A4, A5, A6):
    """
    This function calculates proton impact charge exchange cross sections (in cm2) of 
    H n=1.
    param E: requested electron-impact energy in keV
    type E: float, np.ndarray
    param Ai: fit coefficient 
    type Ai: float
    """
    sigma = 1e-16 * A1 * np.log(A2/E + A6) / (1 + A3*E + A4*E**3.5 + A5*E**5.4)
    return sigma