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Energies of dipole‐bound anionic states
Author(s) -
Gutowski Maciej,
Skurski Piotr,
Jordan Kenneth D.,
Simons Jack
Publication year - 1997
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1997)64:2<183::aid-qua5>3.0.co;2-s
Subject(s) - chemistry , dipole , excited state , electron , atomic physics , zero point energy , bound state , coupled cluster , electron affinity (data page) , binding energy , relaxation (psychology) , dimer , electronic correlation , molecular physics , molecule , physics , quantum mechanics , psychology , social psychology , organic chemistry
Dipole‐bound anionic states of CH 3 CN,C 3 H 2 , and (HF) 2 were studied using highlycorrelated electronic structure methods and extended one‐electron basissets. The electron detachment energies were calculated using the coupledcluster method with single, double, and noniterative triple excitations.Geometrical relaxation of the molecular framework upon electron attachmentand the difference in the harmonic zero‐point vibrational energies betweenthe neutral and the dipole‐bound anionic species were calculated at the MP2level of theory. We demonstrate that the dispersion interaction between theloosely bound electron and the electrons of the neutral molecule is animportant component of the electron binding energy, comparable in magnitudeto the electrostatic electron–dipole stabilization. The geometricalrelaxation upon electron attachment and the change in the zero‐pointvibrational energy is important for the weakly bound HF dimer. Thepredicted values of the vertical electron detachment energies for thedipole bound states of CH 3 CN and C 3 H 2 of112 and 188 cm −1 , respectively, are in excellent agreementwith the recent experimental results of 93 and 171±50cm −1 , respectively. For(HF) 2 − , the predicted value of adiabaticelectron detachment energy is 396 cm −1 , whereas theexperimental vertical detachment energy is 508±24cm −1 . The possibility of formation of the neutral dimer inan excited vibrational state is considered. © 1997 John Wiley& Sons, Inc. Int J Quant Chem 64 : 183–191, 1997