Deuterium Concentrations of H2PO4-and NH4+Radicals in Partially Deuterated NH4H2PO4

Abstract

The deuteration rates (D-rates) of H 2 PO 4 - radicals ( R P ) in partially deuterated NH 4 H 2 PO 4 crystals are measured by ESR of SeO 4 3- doped in the crystals. It is found that the phase transition temperatures ( T c ) of the crystals depend linearly on R p ; T c ( R P ) = 148 + 94 R P [K]. Using this relation and data about total D-rate of highly deuterated ADP obtained by others, D-rates of NH 4 + radicals ( R N ) in the crystals are calculated. It is pointed out that the shift of T c does not depend on R N but on R P .