CollisionDB: DataSet D846

$e^{-} + Be 2 s 3 d^{3} D \to Be 2 s 4 d^{3} D + e^{-}$

Process	EEX: Excitation
Data type	cross section \| uploaded on 2022-05-26
Comment	Analytic fits for electron-impact excitation collision strengths for BeI as a function of energy in terms of threshold
Recommended	Yes

Method	Theory
Columns	E /eV sigma /cm²
Threshold	0.73001 eV
Uncertainty	15 %
Ref	B7: Dipti, T. Das, K. Bartschat, I. Bray, D. Fursa, O. Zatsarinny, C. Ballance, H. Chung, Y. Ralchenko, "Recommended electron-impact excitation and ionization cross sections for Be I ", Atomic Data and Nuclear Data Tables 127-128, 1-21 (2019). [10.1016/j.adt.2018.11.001]
Data	Download (data from fit)

Fitted Data

Fit Function
Details

Ω (x) = (\frac{x (x - 1)}{x^{2} + A_{1}}) (A_{2} + \frac{A_{3}}{x} + \frac{A_{4}}{x^{2}} + \frac{A_{5}}{x^{3}} + \frac{A_{6}}{x^{4}})

Python

def DF_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*(x-1)/(x**2 + A1))*(A2 + A3/x + A4/x**2 + A5/x**3 + A6/x**4)
    return Omega

Data Type

collision strength

Fit Coefficients

A1	1.477e+01
A2	2.808e+02
A3	-3.131e+03
A4	2.537e+04
A5	-5.692e+04
A6	4.285e+04

x-range

–

DataSet D846

e−+Be2s3d3D→Be2s4d3D+e−

Fitted Data

$e^{-} + Be 2 s 3 d^{3} D \to Be 2 s 4 d^{3} D + e^{-}$