ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Electric-field-enhanced laser-induced plasma spectroscopy is a relatively simple and general approach to the mapping of electronic states and internal mode structure in small metal-based molecular complexes. In an exemplary study, weakly bound excited-state ion–molecule complexes of aluminum have been formed and monitored. Emission spectra associated with Al+CO(Al+OC) and Al+H2 complexation show clear vibrational structure tentatively associated with the Al+ -molecule stretch and/or triatomic bending mode. These features are correlated precisely with transitions among several excited states of the Al+ ion which extend throughout the visible and ultraviolet. Evidence is also obtained for Al+N2 complexation associated with select Al+ excited states. All complex emissions which can be readily ascribed involve singlet-(Al+) –singlet-(CO,H2,N2) interactions. Resulting singly charged electronically excited molecular-ion complexes are likely formed in orbiting collisions of the Al+ ion. Observed vibrational-level separations are consistent with quantum-chemical calculations on the ground electronic 1Σ states of Al+CO, Al+OC, Al+H2, and Al+N2. Broadening and vibrational structure associated with an Al++–N2 interaction are apparent, as excited-state complex formation in this system dominates that for the Al++–CO interaction. These results are considered in view of an anticipated Coulomb explosion in multiply charged ions. Extensions to the vacuum ultraviolet for the study of weakly bound ground-state Al+ complexes and extrapolations to other metal-based systems are suggested.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.461395
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