Higher order VO_n defects

The 889 cm^-1 defect also anneals out around 450$^\circ$C, whereupon LVMs around 910, 976 and 1005 cm^-1 (10K) are found. The intensities of these LVMs appear to be correlated. Another band at 986 cm^-1 also arises but its intensity is not correlated with the other three. Corbett et al [141] assign the three LVMs to VO₃ where O_i is trapped near the VO₂ centre, since at this temperature O_i is now mobile. Thus VO₂ does not dissociate but traps O_i. Support for this assignment is that the rate of growth of 976 cm^-1 line is proportional to the product of the intensities of the 889 cm^-1 line and that due to O_i [90]. However, the interpretation here is dependent on the assignment of the 889 cm^-1 defect.

Further lines have also been seen and tentatively assigned to VO₄ complexes, and a study of higher order VO_n defects is currently underway by Lindström and Hallberg.