A cusp in low energy electron-sodium scattering

Negative-ion resonances in total cross sections for slow electron-sodium collisions

“…Johnston and Burrow [15] observed a structure at 2.0-2.2 eV that contained the overlapping of 3p3p 1 D and 3p4s 1 P o resonances and a Wigner cusp due to the opening of the first inelastic channel. Another experiment of Andrick, Eyb, and Hofmann [10] for the differential elastic scattering also showed the strong influence of the 1 D and 1 P resonances near 3p excitation threshold in cross sections. The next peak that we locate at 2.55 eV with 3 F symmetry should correspond to the feature at 2.57 eV with a configuration of 3p3d 3 F as observed by Johnston and Burrow [15].…”

“…Negative-ion formation in electronsodium (e-Na) scattering has attracted substantial theoretical and experimental efforts owing to its extreme sensitivity to the electron correlation effects. Experimental studies for sodium negative-ion resonances have been carried out in electron scattering [6][7][8][9][10][11][12], laser photodetachment technology [13], and electron transmission spectroscopy [14,15]. On the theoretical side, the low-lying negative-ion states were predicted by several different theoretical models, such as the close-coupling approach [16][17][18], the multiconfigurational Hartree-Fock method [19], and variational [20], effectiverange [21], and relativistic R-matrix techniques [22].…”

Interview with N. Bloembergen

“…Measurements for the first inelastic threshold for e--Na and e--K scattering have already been reported (Andrick et al 1972, Eyb andHofmann 1975). The present work deals with the e--K cross section in the energy range of the second, third M Eyb and fourth excited states of potassium where three resonances have been found in the elastic cross section.…”

“…In some cases as, for instance, the elastic scattering of electrons on noble gases below the first excited state, it is possible to get all the information about a resonance state from the angular dependence of the profile of the resonance (see for instance Andrick 1973) ie the complete set of quantum numbers, the phaseshifts of the direct scattering and from them the natural linewidth of the resonance, the polarization if given etc.…”

Optical potential approach to electron and positron scattering from noble gases. I. Argon

“…We have therefore chosen to augment the straightforward yet robust method of polarised orbitals with an optical potential to take the excited states into account. We have used the method of Bransden and Coleman (1972) (see also Scott andBransden 1981, Callaway andOza 1985) for this purpose.…”