DataSet D107429

\[\mathrm{e}^- + \mathrm{Li} \; 4f \rightarrow \mathrm{Li}^{+} + 2\mathrm{e}^-\]

Process EIN: Ionization
Data type cross section | uploaded on 2022-11-11
Comment Using Lotz formula from Lotz et al. (Eq.1) with Data Set 1B in Wutte et.al. (p 166) combined with 4f ionization energy from Wang et al.
Methodsemi-empirical
Columns
  1. E /eV
  2. sigma /cm2
Threshold0.850 eV
Ref
  • B18: D. Wutte, R.K. Janev, F. Aumayr, M. Schneider, J. Schweinzer, J.J. Smith and H.P. Winter, "CROSS SECTIONS FOR COLLISION PROCESSES OF Li ATOMS INTERACTING WITH ELECTRONS, PROTONS, MULTIPLY CHARGED IONS, AND HYDROGEN MOLECULES", Atomic Data and Nuclear Data Tables 65, 155-180 (1997). [10.1006/adnd.1997.0736]
  • B29: Z. -W Wang, X. -W Zhu, K. T Chung, "Energy and fine structure of 1s2nd and 1s2n f states for the lithium isoelectronic sequence ", Journal of Physics B: Atomic, Molecular and Optical Physics 25, 3915-3927 (1992). [10.1088/0953-4075/25/19/006]
DataDownload (data from fit)

Fitted Data

Fit Function
Details		 \[\begin{align*} \sigma_{e}^{ion}\big(E\big) = 10^{-14} \Bigg(\frac{4}{EI} \ln\bigg(\frac{E}{I}\bigg)\Bigg[1-0.7 exp\bigg(\frac{-2.4(E-I)}{I} \bigg) \Bigg] \\ + \frac{8.2}{58E} \ln\bigg(\frac{E}{58}\bigg)\Bigg[1-0.6 exp\bigg(\frac{-0.6(E-58)}{58} \bigg) \Bigg]\Bigg) \end{align*}\]
Python 
def li_ein_lotz(E, I):
    """
    This function calculates electron impact ionization cross sections (in cm2) of 
    Li 4s to 4f.
    param E: requested electron-impact energy in eV
    type E: float, np.ndarray
    param I: ionization energy in eV
    type I: float
    """
    sigma = 1e-14* ((1*4*np.log(E/I)/(E*I))*(1-0.7*np.exp(-2.4*(E/I -1))) + 
                       (2*4.2*np.log(E/58)/(E*58))*(1-0.6*np.exp(-0.6*(E/58 -1))))
    return sigma
Fit Precision10.0 %
Fit Coefficients 
I
 8.505e-01
x-range 0.85103 –