Muonium spin relaxation in carbon monoxide

The spin relaxation of Mu was measured in mixtures of CO and Ar al pressures up to 270 atm and at various magnetic fields. The relaxation rate increased with magnetic field in the way expected for electron spin-exchange processes, though the effect declined at high pressures. We describe the results in terms of spin relaxation of Mu-formyl radicals, MuCO, which break up to give depolarized Mu at low pressures, but are increasingly stabilized at higher pressures.