Hyperfine interaction and structure of a gallium arsenide cluster : Ga2As3

Vapor species produced by laser heating of gallium arsenide crystals were allowed to aggregate in a relatively high pressure of argon or krypton before condensation of the matrices at 4 K. Electron-spin resonance (ESR) identified the spectrum of the S=1/2 Ga2As3 cluster via the 69,71Ga (I=3/2) and 75As (I=3/2) hyperfine structure as containing two equivalent Ga and three equivalent As nuclei. Its geometry is therefore trigonal bipyramid and its ground state probably 2A2″, as obtained by Lou et al., from local-spin-density theory. The observed hyperfine parameters indicate that the unpaired spin is confined almost entirely to the two axial gallium atoms.