ISSN:
1434-6079
Keywords:
31.20.Tz
;
33.20.Lg
;
36.40.+d
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Quantum chemical ab initio calculations have been performed for the vertical excitation energies and oscillator strengths of all low-lying electronically excited states of small helium cluster ions, He n + ,n=2, ..., 7. The geometrical structures of the ions were fixed at the equilibrium geometries of the respective ground states, for He 4 + and He 5 + also one alternative structure was considered. The low-lying excited states can be classified into two categories: the electronic transition can occur either within the central He 2 + or He 3 + unit or from the peripheral weakly bound He atoms to this unit. The latter transitions are very weak (f≈0.001), closely spaced, with vertical excitation energies of about 5.7 eV. The He 2 + and He 3 + units have strong transitions at 9.93 and 5.55 eV, respectively; these transitions are only slightly blue-shifted if He 2 + or He 3 + are placed as “chromophores” into the centre of a larger He n + cluster. The large difference in the vertical excitation energy of the strong transition should enable an experimental decision of the question whether the cluster ions have He 2 + or He 3 + cores.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01437257
