``Frequently the approximations that enter solid state calculations are so intricate that they are never specified in the publication in which the calculations are described and would not be of interest if they were. Nevertheless, without knowledge of the approximations, it is sometimes difficult to assess a result that is characterised only as being the best the author could do.''W. A. Harrison, 1980

`Electronic Structure and the properties of solids'

In this chapter I will describe how LSDF theory has been implemented in AIMPRO. I will also discuss some of the practical problems encountered when using AIMPRO and how these can be minimised. A full review of the methodology behind AIMPRO is given in Reference [36] and vibrational mode calculations in Reference [37].

- Expanding the Wavefunction
- Approximation to the charge density
- Self-consistency
- Evaluation of Forces
- Structural Optimisation
- Calculation of Vibrational Modes
- Discussion of the methods used in AIMPRO
- Application of AIMPRO to the oxygen in silicon problem