Value Description
alpha Convert based on the alpha part of the name only. Leading or trailing numbers and symbols are discarded. The alpha part is assumed to be an element symbol
auto Attempts several of the other conversions of increasing complexity until a match is found
ff Search through the names of atomtypes in currently-loaded forcefields, assigning elements based on matches found
firstalpha Convert based on the first alpha part of the name only (i.e. until a non-alpha character is found). The alpha part is assumed to be an element symbol
name The name is assumed to be an actual element name, and is converted to the relevant element number
numeric Use the numeric part of the name as the element number
singlealpha Convert based on the first alphabetic character encountered - useful only when single-character element symbols are likely to be found (e.g. for pure organic CHON systems)