Resonant interaction between localized and extended vibrational modes in Si: ¹⁸O under pressure

Hydrostatic pressure were used to bring the 1084 cm^-1 stretch mode of ¹⁸O_i into resonance with a second harmonic of the 517cm^-1 resonant mode. As such, the interaction between the two modes resulted in an anticrossing of the frequencies. Since the frequency of the resonant mode lies within the continuum of lattice two-phonon states, this interaction also provides information regarding the decay of local vibrational modes (LVMs) into lattice phonons. Such knowledge was useful because vibrational relaxation mechanisms affect properties such as diffusion and energy transfer involving oxygen impurities in silicon.