Long-range electron binding to quadrupolar molecules

Charles Desfrançois (1) , Y. Bouteiller (1) , J. P. Schermann (1) , D. Radisic (2) , S.T. Stokes (2) , K. H. Bowen (2) , N. I. Hammer (3) , R.N. Compton (3)

1 LPL - Laboratoire de Physique des Lasers
2 BOWEN'S GROUP - Department of Chemistry
3 COMPTON'S GROUP - Deprtment of Physics and Chemistry

An excess electron can be bound to a molecule in a very diffuse orbital as a result of the long-range contributions of the molecular electrostatic field. For a molecule with a null dipole the first non-vanishing field left is the quadrupolar field. Theoretical results for quadrupole-bound anions have been rather conflicting and the few experimental reports can have alternative explanations. Following a systematic search, we report experimental evidence that such quadrupole binding occurs for the trans-succinonitrile molecule (EA = 20 ± 2 meV), while the gauche-succinonitrile conformer supports a dipole-bound anion state (EA = 108 ± 10 meV). Theoretical calculations at the DFT/B3LYP level support these interpretations and give electron affinities of 20 and 138 meV, respectively.

Mots clés: quadrupole-bound anions; succinonitrile; Rydberg electron transfer; Photoelectron spectroscopy; Quantum Chemistry calculations

Domaines: Physique Quantique [quant-ph]; Chimie-Physique [physics.chem-ph]

Charles Desfrançois, Y. Bouteiller, J. P. Schermann, D. Radisic, S.T. Stokes, et al.. Long-range electron binding to quadrupolar molecules. Physical Review Letters, 2004, 92, pp.083003. ⟨10.1103/PhysRevLett.92.083003⟩. ⟨hal-00002344⟩