Title

Reinvestigation of the aluminum hydride (AlH+ and AlD+) cation radicals by ESR in argon matrices at 4 K: Generation by reactive laser sputtering

ACS Citation

Knight, L. B.; Cobranchi, S. T.; Gregory, B. W.; Earl, E. A. Reinvestigation of the aluminum hydride (AlH+ and AlD+) cation radicals by ESR in argon matrices at 4 K: Generation by reactive laser sputtering. J. Chem. Phys. 1987, 86, 3143-3143.

Abstract

The ESR spectra previously assigned to the AlH+ radical ion (X-€‰ 2Σ) J. Chem. Phys. 7 1, 3991 (1979)] actually belong to the divalent neutral aluminum radical AlHOH whose charge distribution and electronic structure can be described as AlH+OH-ˆ’ with 90% of the unpaired electron on the AlH+ part of the molecule. Reactive laser sputtering and photoionization of AlH(g) were used to generate the AlH+ and AlD+ cation radicals, whose ESR spectra have been observed for the first time. A detailed analysis of the ESR results for argon matrices at 4 K reveal unusually large Alhyperfine interaction (hfi) with A iso and A dip values of 1586(2) and 49(1) MHz, respectively. The H hfi is essentially isotropic with A iso=442(2) MHz. The observed nuclear hyperfineAtensors for Al and H show excellent agreement with a b i n i t i o CI theoretical calculations. The results for AlH+ are compared with the isoelectronic neutral radical MgH, and the similar AlF+ cation radical. The Al hfi is slightly larger in AlD+ relative to AlH+. This interesting isotopic effect is qualitatively explained on the basis of electronic structure dependence on small changes in the bond distance for the two isotopic radicals.

Source Name

Journal of Chemical Physics

Publication Date

1-1-1987

Volume

86

Issue

6

Page(s)

2314-2320

Document Type

Citation

Citation Type

Article