Interatomic Coulombic decay in a He dimer: Ab initio potential-energy curves and decay widths
- Faculty of Mathematics and Physics, Institute of Theoretical Physics, Charles University in Prague, V Holesovickach 2, 180 00 Prague (Czech Republic)
- Theoretische Chemie, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)
The energy gained by either of the two helium atoms in a helium dimer through simultaneous ionization and excitation can be efficiently transferred to the other helium atom, which then ionizes. The respective relaxation process called interatomic Coulombic decay (ICD) is the subject of the present paper. Specifically, we are interested in ICD of the lowest of the ionized excited states, namely, the He{sup +}(n=2)He states, for which we calculated the relevant potential-energy curves and the interatomic decay widths. The full-configuration interaction method was used to obtain the potential-energy curves. The decay widths were computed by utilizing the Fano ansatz, Green's-function methods, and the Stieltjes imaging technique. The behavior of the decay widths with the interatomic distance is examined and is elucidated, whereby special emphasis is given to the asymptotically large interatomic separations. Our calculations show that the electronic ICD processes dominate over the radiative decay mechanisms over a wide range of interatomic distances. The ICD in the helium dimer has recently been measured by Havermeier et al. [Phys. Rev. Lett. 104, 133401 (2010)]. The impact of nuclear dynamics on the ICD process is extremely important and is discussed by Sisourat et al. [Nat. Phys. 6, 508 (2010)] based on the ab initio data computed in the present paper.
- OSTI ID:
- 21442948
- Journal Information:
- Physical Review. A, Vol. 82, Issue 1; Other Information: DOI: 10.1103/PhysRevA.82.013422; (c) 2010 The American Physical Society; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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CONFIGURATION INTERACTION
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EXCITATION
EXCITED STATES
GREEN FUNCTION
HELIUM
HELIUM IONS
INTERATOMIC DISTANCES
IONIZATION
POTENTIAL ENERGY
RADIATIVE DECAY
RELAXATION
CHARGED PARTICLES
COLLISIONS
DECAY
DISTANCE
ELEMENTS
ENERGY
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
FLUIDS
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GASES
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NONMETALS
PARTICLE DECAY
RARE GASES