ENDOR Study of X-Irradiated Single Crystals of Ice

ENDOR measurements were made on x‐irradiated single crystals of hexagonal ice. The ENDOR frequencies yield the hyperfine coupling for the OH radicals produced in irradiated ice. The method is capable of distinguishing between OH radicals produced in three different environments. The principal values of the hyperfine coupling tensors in megacycles per second of the three distinct OH radicals are as follows: $$\begin{array}{cccc}& \mathrm{Axx}& \mathrm{Ayy}& \mathrm{Azz}\\ (\mathrm{I})& \text{−\hspace{0.17em}80.0}& \text{−\hspace{0.17em}124.4}& \text{+\hspace{0.17em}9.2}\\ (\mathrm{II})& \text{−\hspace{0.17em}81.2}& \text{−\hspace{0.17em}124.4}& \text{+\hspace{0.17em}19.4}\\ (\mathrm{III})& \text{−\hspace{0.17em}78.2}& \text{−\hspace{0.17em}126.2}& \text{+\hspace{0.17em}15.6}\end{array}$$ Using ESR spectra in conjunction with ENDOR data, the $g$ tensors were also determined with the following results: $$\begin{array}{cccc}& \mathrm{gxx}& \mathrm{gyy}& \mathrm{gzz}\\ (\mathrm{I})& \text{2.0028}& \text{2.0089}& \text{2.0597}\\ (\mathrm{II})& \text{2.0031}& \text{2.0089}& \text{2.0571}\\ (\mathrm{III})& \text{2.0027}& \text{2.0088}& \text{2.0581}\end{array}$$