Influence of clustering and molecular orbital shapes on the ionization enhancement in ammonia

Scott Sayres, Matt W. Ross, A. W. Castleman

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The Coulomb explosion of clusters is known to be an efficient source for producing multiply charged ions through an enhanced ionization process. However, the factors responsible for obtaining these high charge states have not been previously explored in detail and remain poorly understood. By comparing intensity-resolved visible laser excitation experiments with semi-classical theory over a range spanning both multiphoton and tunneling ionization regimes, we reveal the mechanism in which extreme ionization proceeds. Under laser conditions that can only singly ionize individual molecules, ammonia clusters generate ions depleted of all valence electrons. The geometries of the molecular orbitals are revealed to be important in driving the ionization, and can be entirely emptied at the energy requirement for removal of the first electron in the orbital. The results are in accord with non-sequential ionization arising from electrons tunneling from three separate molecular orbitals aided through the ionization ignition mechanism.

Original languageEnglish (US)
Pages (from-to)12231-12239
Number of pages9
JournalPhysical Chemistry Chemical Physics
Volume13
Issue number26
DOIs
StatePublished - Jul 14 2011
Externally publishedYes

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Molecular orbitals
Ammonia
Ionization
ammonia
molecular orbitals
ionization
orbitals
augmentation
Ions
energy requirements
Laser excitation
Electron tunneling
Electrons
electron tunneling
ignition
Explosions
lasers
Ignition
explosions
ions

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Influence of clustering and molecular orbital shapes on the ionization enhancement in ammonia. / Sayres, Scott; Ross, Matt W.; Castleman, A. W.

In: Physical Chemistry Chemical Physics, Vol. 13, No. 26, 14.07.2011, p. 12231-12239.

Research output: Contribution to journalArticle

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