ESR investigation of the phosphorous-rhenium center in gamma-irradiated phosphate-doped ammonium perrhenate

Single crystals of ammonium perrhenate (NH4ReO4) doped with PO43- and gamma-irradiated at RT (300 K) give rise to paramagnetic centers which could be recorded both at RT and 77 K. The radical has been identified as a pseudo V-k center, namely a PO42- radical associated with ReO4-. The g-tensor and the hyperfine A-tenser are found to be axially symmetric and are discussed in detail.