EPR STUDY OF ALKALI-METAL ATOMS IN HYDROCARBON MATRICES

A rotating cryostat was used to trap the Group 1 metal atoms in adaman tane and cyclohexane matrices at 77 K. Electron paramagnetic resonance spectra of matrix-isolated atoms were obtained in adamantane at X- an d Q-band frequencies. The magnetic parameters were calculated from exa ct solutions of the Breit-Rabi equation and compared with values in th e gas phase acid in rare gas matrices, The EPR spectra show no evidenc e for g and/or hyperfine anisotropy. Consequently, there is no evidenc e for the dipolar state of these atoms. Furthermore, trimers, pentamer s and/or septamers are not formed from Rb and Cs under experimental co nditions that have led to the formation of Li-3, Li-5, Na-3 and K-7. G roup 1 atoms in a solid cyclohexane matrix give only colloidal metal p articles with an average diameter of less than 10(2) Angstrom.