Isomorphous substitution in non-linear optical KTiOPO4: neutron powder diffraction study of KTiO(P0.5As0.5)O4

Abstract

The structure of KTiO(P_0.5As_0.5)O₄ has been determined by time-of-flight neutron diffraction Pn2₁a, a= 12.9695(8)Å, b= 10.6898(7)Å, c= 6.4932(4)Å, V= 900.2(2)ų, R_p= 2.88, _wR_p= 4.23. The arsenic atoms enter the phosphorous sites in a random fashion. Powder second-harmonic generation (SHG) data reveal a correlation between the Ti(1)— O(9)— Ti(2) bond angle and the non-linear optical (NLO) coefficient in the KTiOP_{1 –x}As_xO₄system.