Electron-impact excitation of carbon

Abstract

The B-spline R-matrix method is used to investigate the electron-impact excitation of neutral carbon over an energy range from threshold to 60 eV. A multiconfiguration Hartree-Fock method with nonorthogonal orbitals is employed to generate an accurate representation of the target wavefunctions. The present close-coupling expansion includes the bound and autoionizing states of neutral carbon derived from the 1s 2 2s 2 2p 2 , 1s 2 2s 2 2p3ᐉ ͑ᐉ =0,1,2͒, 1s 2 2s 2 2p4s, 1s 2 2s2p 3 , and 1s 2 2p 4 configurations, plus eight pseudostates to fully account for the polarizability of the ground state of atomic carbon. Cross sections and effective collision strengths are presented for important transitions from the ground state 2p 2 3 P, and the metastable 2p 2 1 D and 1 S states. Our predictions for the cross sections show significant discrepancies with those from previous calculations carried out with the standard R-matrix approach in a similar scattering model ͓Dunseath et al., J. Phys. B 30, 277 ͑1997͒ ͔. These discrepancies are mostly due to the different target descriptions, with the present one giving overall superior agreement with experiment for energy levels and oscillator strengths. The excitation cross sections exhibit prominent resonance structures in the low-energy region. The energy positions, widths, and classifications for the detected resonances are presented.

The differential cross sections of electron scattering on neutral boron

“…напр., [3][4][5][6]). Хоча електронна оболонка атома бору 1s 2 2s 2 2p 2 P o , що міс-тить всього п'ять електронів, належить до достатньо простих атомних структур, екс-периментальні перерізи збудження його станів електронним ударом не визначені.…”

“…Будова атома бору була розрахована методом R-матриці з B-сплайнами за допомогою про-грамного пакету BSR [12]. Останній неод-норазово використовувався нами для дос-ліджень електрон-атомного розсіяння, по-чинаючи від перших застосувань до атомів C [5] і Са [13][14] та закінчуючи недавніми розрахунками атома F [15]. Ключовою особливістю цього підходу є істотне по-ліпшення опису мішені шляхом викорис-тання компактних розкладів взаємодії конфігурацій, що включають неортогона-льні набори залежних від терму одноелек-тронних орбіталей.…”

Electron Stark Broadening Database for Atomic N, O, and C Lines

“…ff , and the cross term. For electron-atom collisions, one of the most successful closed coupling approaches for computing the collisional cross section is the R-matrix with pseudo states (RMPS) method [15,16]. However, the RMPS method can only handle a limited number of states, not the complete spectrum of states required in a Stark line shape calculation.…”

Contribution to the theoretical investigation of electron and photon interaction with carbon atom and its ions

“…In the last two decades, the most detailed works have been reported by Dunseath et al [37], Zatsarinny et al [38] and Liu, Wang and Zhou [39]. In the work by Dunseath et al [37], two independent standard R-matrix calculations were performed.…”

“…In their work, Zatsarinny et al [38] presented theoretical results based on the extended version of the R-matrix method, where a B-spline basis is employed for the representation of the continuum functions. These authors revealed a prominent resonance structure for the most electron-induced transitions in atomic carbon at low energies.…”