10.4.4 Adding a New Short-Contact Definition; The Define Short Contacts Dialogue Box

Hit the Contacts... button (located near to the bottom-centre of the main Mercury window), or select the top-level Calculate option followed by Contacts.... in the resulting pull-down menu, to bring up the Contacts dialogue box. Then hit Add in the Contacts dialogue box and pick Short... to bring up the Define Short Contacts dialogue box.

Alternatively, you can get straight to the Define Short Contacts dialogue by right-clicking anywhere in the white list box under the main Mercury display area and selecting Add Short... from the resulting menu.

Set the required upper distance limit - this must be a distance expressed relative to the sum of the vdW radii of the atoms (see Section 10.4.1).

Specify whether the contacts are to be intermolecular only, intramolecular only, or whether both are allowed.

If intramolecular bonds are allowed, specify the minimum number of covalent bonds between the contact atoms (see Section 10.4.2).

You cannot specify the element types of the interacting atoms; any element type will be allowed. Create a specific contact definition if you are only interested in contacts between particular types of atoms (see Section 10.4.5).

The following settings will find intermolecular and intramolecular contacts between any pair of atoms, subject to the constraints that (a) the contact must be at least 0.3Å shorter than the sum of vdW radii, and (b) if the contact is intramolecular, the atoms must be separated by at least 4 covalent bonds:

Hit Default followed by Apply if you want to return all the settings to their default values.