CollisionDB: DataSet D108023

\[\mathrm{He}^{2+} + \mathrm{H} \; n=2 \rightarrow \mathrm{He}^{2+} + \mathrm{H} \; n=10\]

Process	HEX: Excitation
Data type	cross section \| uploaded on 2023-02-08
Comment	Fit function taken from p98. Error: E<5keV/u -> 100%, 5keV/u<E<20keV/u -> 40%, 20keV/u<E<200keV/u -> 30%, E<200keV/u -> 20%

Method	semi-empirical
Frame	Target
Columns	E /eV u^-1 sigma /cm²
Ref	B37: R. K. Janev, J. J. Smith, "Cross sections for collision processes of hydrogen atoms with electrons, protons, and multiply charged ions", IAEA- Atomic and Plasma–Material Interaction Data for Fusion, Vienna 4 (1993). [https://www.iaea.org/publications/1839/atomic-and-plasma-material-interaction-data-for-fusion]
Data	Download (data from fit)

Fitted Data

Fit Function
Details

\[\sigma_{ex}^{2\rightarrow n > 5}(E) =10^{-16}A_1A_7 \Bigg[\frac{e^{-\frac{A_2}{E}}\ln(1+A_3E)}{E} + \frac{A_4e^{-A_5E}}{E^{A_6}}\Bigg]\]

Python

def h_hex_janev_2n(E, A1, A2, A3, A4, A5, A6, A7):
    """
    This function calculates proton impact excitation cross sections (in cm2) of 
    H n=2 to n>5 and n=3  to n>6 and for He+2 of H n=2 to n>5 and n=3 to n>6
    param E: requested impact energy in keV/u
    type E: float, np.ndarray
    param Ai: fit coefficient 
    type Ai: float
    """
    sigma = 1e-16 * A1 * A7 * (np.exp(-A2/E) * np.log(1 + A3*E) / E + A4*np.exp(-A5*E)/E**A6)
    return sigma

Fit Precision

1.0 %

Fit Coefficients

A1	7.306e+01
A2	3.795e+01
A3	1.453e+00
A4	2.460e-03
A5	1.585e-01
A6	-1.478e+00
A7	6.050e-02

x-range

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