F mota - furtado and pf o’mahony, theoretical triple differential cross sections for the simultaneous ionization and excitation of helium, in: invited papers and progress reports of the 3rd european conference on (e, 2e) collisions and related problems, g stefani, ed, area della ricerca di roma, italy, pl (1990. Calculation of the double-photoionization cross section of helium cheng pan and h p kelly excitation - ionization by photoabsorption at low and intermediate energies jian-zhi tang and joachim burgdörfer a high-resolution study of the threshold photoelectron spectrum of helium d b thompson, p bolognesi, m coreno et al. In the helium energy level diagram, one electron is presumed to be in the ground state of a helium atom, the 1s state an electron in an upper state can have spin antiparallel to the ground state electron (s=0, singlet state, parahelium) or parallel to the ground state electron (s=1, triplet state, orthohelium.
Early experimental work on the helium ionization– excitation problem was performed in coplanar 34 or noncoplanar 35,36 scattering geometries under electron energies of 1600 and 600 ev, respectively, and ejected-electron energies of 10, 20, and 40 evasymmetric measure. Helium energy levels the helium ground state consists of two identical 1s electrons the energy required to remove one of them is the highest ionization energy of any atom in the periodic table: 246 electron volts the energy required to remove the second electron is 544 ev, as would be expected by modeling it after the hydrogen energy levels the he+ ion is just like a hydrogen atom with two units of charge in the nucleus.
Values from crc are ionization energies given in the unit ev other values are molar ionization energies given in the unit kj/mol the first of these quantities is used in atomic physics, the second in chemistry, but both refer to the same basic property of the element.
The differential and total cross sections are calculated for the ionization of helium-like ions that is accompanied by the excitation of residual ions to ns states owing to an electron impact nonrelativistic perturbation theory in electron–electron interaction with coulomb functions used for a.
This original experiment as done using mercury vapor and our experiment will use a form of helium gas used by hertz in 1923 the transfer of energy to atoms must occur in discrete amounts this can be accomplished by inelastic/elastic collisions of atoms with a beam of electrons at low energies (low electron velocities) an continue reading excitation and ionization energies of helium. Simultaneous excitation-ionization of helium to the hec2p/ionic state by electron impact is studied experimentally and theoretically electron–photon angular correlations energy and by.
S bellm et al, absolute cross sections for the ionization-excitation of helium by electron impact,physical review a: atomic, molecular, and optical physics , american physical society (aps), sep 2008.