The location of the pseudopotential libraries

In this BLOCK the user tells CASTEP where the pseudopotentials can be found

%BLOCK SPECIES_POT

$\begin{array}{ccc} \begin{displaymath} XX_{1} or I_{1} & <filename> \\ \vdots & \vdots \\ XX_{n} or I_{n} & <filename> \end{array}$

%ENDBLOCK SPECIES_POT

The species symbol/atomic number must be consistent with that in the IONIC_POSITIONS block and the SPECIES_MASS block. If the pseudopotential files are contained in a working directory then only the filename is specified. If the user is working on a shared machine such as a cluster in which the pseudopotentials are kept in a library for access by multiple users then the full directory path must be specified.