The effects of anionic impurities on the growth habit and optical properties of KDP

Some anionic impurities (sodium metaphosphate, potasium pyrophosphate, formic acid, acetic acid, oxalic acid and tyrosine) were found to have an inhibiting effect on the growth of KDP crystals. Complete stoppage of pyramidal face growth was observed in the presence of high concentration of both [Hx-n(PO3)(x)](n-) and [H2P2O7](2-), and in these cases the crystal habit was changed into a closed octahedron and the whole crystal stopped growing. It was proposed that the inhibition is caused by the adsorption of the anions at the growing crystal surface, especially the pyramidal surface through the formation of H-bond between the anions and the H2PO4- groups. The anions have a harmful effect on the laser damage threshold due to possible incorporation. (C) 1999 Elsevier Science B.V. All rights reserved.