Data type: char
difmap 'difference Fourier map'
vecmap 'real-space vector search'
heavy 'heavy-atom method'
direct 'structure-invariant direct methods'
geom 'inferred from neighbouring sites'
disper 'anomalous-dispersion techniques'
isomor 'isomorphous structure methods'
Codes which identify the methods used to locate the initial atomic sites. The *_primary code identifies how the first atom sites were determined; the *_secondary code identifies how the remaining non-hydrogen sites were located; and the *_hydrogens code identifies how the hydrogens were located.