CollisionDB: DataSet D108107

\[\mathrm{e}^- + \mathrm{H} \; n=3 \rightarrow \mathrm{H}^{+} + 2\mathrm{e}^-\]

Process	EIN: Ionization
Data type	cross section \| uploaded on 2023-02-08
Comment	Fit function and data were taken from Janev et al. p36. Errors: E<4eV -> 60%, 4eV<E<30eV -> 20%, E>30eV -> 10%.

Method	semi-empirical
Columns	E /eV sigma /cm²
Threshold	1.511 eV
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

\[\sigma_{ion} (E) = \frac{10^{-13}}{IE} \Bigg[A_1 \ln \bigg( \frac{E}{I} \bigg) + \sum_{j=1}^5 A_{j+1}\bigg(1 - \frac{E}{I} \bigg)^j \Bigg]\]

Python

def h_ein_janev(E, A1, A2, A3, A4, A5, A6, I):
    """
    This function calculates electron impact ionization cross sections (in cm2) of 
    H n=1, 2, 3.
    param E: requested electron-impact energy in eV
    type E: float, np.ndarray
    param Ai: fit coefficient 
    type Ai: float
    param I: ionization energy in eV
    type I: float
    """
    sigma = 1e-13/(E*I)*(A1*np.log(E/I)+A2*(1-I/E) +  A3*(1-I/E)**2
                     + A4*(1-I/E)**3 + A5*(1-I/E)**4 + A6*(1-I/E)**5)
    return sigma

Fit Precision

0.6 %

Fit Coefficients

A1	5.846e-02
A2	-5.127e-02
A3	8.531e-01
A4	-5.701e-01
A5	7.668e-01
A6	0.000e+00
I	1.511e+00

x-range

1.511 –