Fit Function: SF_fit_Be

Fit Function \[\Omega (x) = \left( \frac{x - 1}{x^{A_1} + A_2} \right) \left(A_3 + \frac{A_4}{x} + \frac{A_5}{x^2} + \frac{A_6}{x^3} \right)\]
Comments Python code requires NumPy imported as `np`.

Python

Arguments
namedescriptionunitstype(s)
x energy in threshold units float, np.ndarray
A1 fit coefficient float
A2 fit coefficient float
A3 fit coefficient float
A4 fit coefficient float
A5 fit coefficient float
A6 fit coefficient float
Return values
namedescriptionunitstype(s)
sigma cross section cm2 float, np.ndarray
Code 
def SF_fit_Be(x, A1, A2, A3, A4, A5, A6):
    """
    This function calculates the dimensionless collision strengths for electron 
    impact excitation of BeI.
    param x: requested electron-impact energy in threshold units
    type x: float, np.ndarray
    param Ai: fit coefficients
    type Ai: float
    """
    Omega = ((x - 1)/(x**A1 + A2))*(A3 + A4/x + A5/x**2 + A6/x**3)
    return Omega