Electron scattering from silicon

Abstract

The B-spline R-matrix method is used to study electron collisions with neutral silicon over an energy range from threshold to 100 eV. The multiconfiguration Hartree-Fock method with non-orthogonal orbitals is employed for an accurate representation of the target wave functions. The present close-coupling expansion includes 34 bound states of neutral silicon derived from the [Ne]3s 2 3p 2 , 3s3p 3 , 3s 2 3p4s, 3s 2 3p5s, 3s 2 3p4p, 3s 2 3p5p, 3s 2 3p3d, and 3s 2 3p4d configurations, plus seven pseudostates to fully account for the dipole polarizability of the ground state and the lowest three excited states of atomic silicon. Cross sections are presented for important transitions from the ground 3s 2 3p 2 3 P ground state and the metastable 3s 2 3p 2 1 D and 3s 2 3p 2 1 S states. Both correlation and polarization effects are found to be important for accurate calculations of the cross sections. The sensitivity of the results was checked by comparing data obtained in different approximations. The current predictions represent an extensive set of electron scattering data for neutral silicon.

Electron-impact excitation of argon at intermediate energies

“…This sensitivity seems to be a general trend, as it is also seen in recent calculations for electron-C [53] and electron-Si [54] collisions.…”

Configuration-interaction plus many-body-perturbation-theory calculations of Si i transition probabilities, oscillator strengths, and lifetimes

“…A good agreement of CI+MBPT for weighted oscillator strengths, initially listed in Ref. [6], is also achieved. The results of the other precision theories shown in Table III also agree with experiment.…”

“…The results of the other precision theories shown in Table III also agree with experiment. This comparison is useful to further verify the accuracy of the theory [6], which is used in electron scattering calculations. Finally, lifetime comparison is useful [3] and Breit-Pauli length-form [5] (LBP) calculations; ∆1 and ∆2 are deviations of CI+MBPT and LBP transition probabilities from the experiment; units are 10 6 sec −1 ; the same abbreviated term notations are used as in [3].…”

“…The agreement of Breit-Pauli calculations [5] is also good, although in several cases the deviations exceed several error bars, indicating the theoretical error. In addition to transition probability, the weighted oscillator strengths are also given to include another accurate calculations [6] in comparison. Finally, the comparison for lifetimes is shown in Table IV.…”

“…The directly available experimental data are lifetimes [1][2][3] and branching ratios [3,4], from which transition probabilities and oscillator strengths were derived [3,4]. Precision calculations of transition probabilities and lifetimes were performed in [5] and weighted oscillator strengths in [6]. Semiempirical methods that can accurately reproduce energy levels do not necessarily lead to accurate lifetimes and transitions rates, as illustrated in Ref.…”