Oxygen in silicon is a problem well suited to modelling using AIMPRO.
Oxygen has a rapidly varying potential close to its atomic core which
is much more suited to fitting with real space Gaussian functions than
sets of plane waves. Oxygen related point defects in silicon exhibit
a variety of different defect symmetries which AIMPRO is able to
constrain accurately. Our use of additional fitting functions placed
at bond centred sites means that *d* orbital fitting functions are not
required on the Si atoms, greatly simplifying the computational
problem. Finally, FTIR has proved to be one of the most important
experimental tools used to study these problems, and we are able to
theoretically calculate both the vibrational modes and induced dipole
moments of these modes. In combination with isotopic shift data these
are a good way of comparing experimental data with the theoretical
models.