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

Some anionic impurities (sodium metaphosphate, potasium pyrophosphate, form ic acid, acetic acid, oxalic acid and tyrosine) were found to have an inhib iting 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 c hanged into a closed octahedron and the whole crystal stopped growing. It w as proposed that the inhibition is caused by the adsorption of the anions a t the growing crystal surface, especially the pyramidal surface through the formation of H-bond between the anions and the H2PO4- groups. The anions h ave a harmful effect on the laser damage threshold due to possible incorpor ation. (C) 1999 Elsevier Science B.V. All rights reserved.