In any of the typenames given in the specification of intramolecular interactions, a wildcard character '*' may be used to 'finish off' any or all of the typenames (or replace individual typenames entirely). In doing so, a single definition is able to match more than one set of typenames.

For example:

bonds harmonic
CT    H*    4184.0    1.06
end

will describe bonds between 'CT' and any other atom beginning with an 'H'.

Using a '*' on its own will match any typename in that position. As an extreme example:

angles harmonic
*     *     *     418.4      109.4
end

will match any angle. Be careful - when Aten is creating expressions and searching for specific interactions between atom types, as soon as an intramolecular definition is found that matches it is used, and no further searching is done. So, loose definitions involving wildcards should be put near to the end of the block in which they occur.