Utilities used by CASTEP

• lev1 $\rightarrow$ an interactive menu-driven utility; it needs files with wavefunctions at all $\mathbf{k}$-points generated by CASTEP and then calculates an intermediate file psi2.[option] for one of the options DOS, DOp, SRF or MAP:
  • DOS option: calculate the total DOS, LDOS projected onto spheres as well as LDOS projected on a $s$, $p$, $d$-like AO;
  • DOp options: calculate LDOS projected to thin layers; this is useful for analysing structure of surface states in the case of slab calculations;
  • MAP option: calculate and store partial charge densities in the real space for the specific range of states;
  • SRF option: for the slab calculations, calculate and store $z$-dependent partial charge densities which are partial charge densities integrated in the $xy$-plane parallel to the surface of the slab; this is the simplest way to distinguish surface and bulk states in your slab system
  Eigenvalues calculated on the last iteration of the band-structure run of CASTEP are to be printed out into a special file called band.out. At the last stage, files band.out and psi2.[option] are used to calculate and plot DOS, LDOS, wavefunctions or partial charge densities by running lev00.

• check $\rightarrow$ (is probably redundant by now) reads all files needed to run the CASTEP and tells the user:
  • whether all the parameters in the param.inc file are sufficient for the present job, e.g. number of plane waves, etc.;
  • whether all input files are okay and consistent with each other and with the parameters in the param.inc file.
  • allows you to choose the minimum possible parameters for the CASTEP run
• take $\rightarrow$ checks the convergence of eigenvalues calculated by CASTEP during the band-structure run as well as their correct order; also, it allows one to choose eigenvalues from any desired iteration;
• sum $\rightarrow$ an utility which allows you to split one big CASTEP job into a sequence of smaller jobs with smaller numbers of $\mathbf{k}$-points; if files, produced at each run, are properly named, then the utility sum will ``gather'' the files and will produce the resulting file(s) psi2.[option] and band.out corresponding to just one (big) run of CASTEP.