EPR studies on molybdenum phosphates Mo2P4O15, NaMo3P3O16and BaMo2P4O16in the temperature range 300–4·2K

摘要

EPR studies of molybdenum phosphates, Mo2P4O15, NaMo3P3O16and BaMo2P4O16in the range 300–4·2 K was carried out. Delocalization of 4d1electron on a Mo5+site in the MoO6octahedra occurs due to tunneling process. This gives rise to unresolved EPR lineshapes in all the cases except in Mo2P4O15. The slight indication of hyperfine structure in Mo2P4O15is due to less feasibility of delocalization of the 4d1electron, as MoO6octahedron is connected through a PO4group to only three octahedra as compared with higher numbers in the case of others. The negative g-shift is observed in all the cases due to positive sign of the spin-orbit coupling constant. The decreasing trend in giso-values in Mo2P4O15and NaMo3P3O16with decreasing temperature is observed, whereas in BaMo2P4O16the giso-value increases with decreasing temperatu