Effects of pressure on radiation processes in solid hydrogen: An ESR study

The effect of pressure on yields of H atoms produced by X-irradiation of so lid hydrogen has been studied using electron spin resonance (ESR) spectrosc opy at around 4 K. The yields of H atoms have been found to decrease with a n increase in pressure. We have concluded that the above finding is due to cage effects on the reaction producing H atoms, H-2--> 2H, H-3(+) + e(-)--> 3H, and so on, which should occur during X-irradiation of H-2 molecules in solid hydrogen. The pressure dependence of the yields of H atoms can be ex plained by a large compressibility of solid hydrogen. This also indicates t hat the compressibility is one of the important parameters in radiation-che mical processes in the solid phase. (C) 2000 American Institute of Physics. [S0021-9606(00)01528-2].