No option to load as the asymmetric unit

[jkshenton]

It is very helpful to reduce down (from the full unit cell) to what corresponds to the number of distinct chemical shifts in the solid-state NMR spectrum (i.e., the asymmetric unit).

An alternative could be to have a tool to take in a full unit cell .magres file and output a new .magres file containing just the asymmetric unit cell.

Expanding on issue raised by @AKM2022

[jryates]

In the simple case - 1 molecule in the asymmetric unit - we can select a molecule, display selected, and unshow the unit cell. At this point only the single molecule is shown.

Loading the asymmetric cell is useful - but a bit of a blunt instrument. It might be worth exploring how the selection of atoms might be extended (i.e. by making it possible to add to a selection - or even "select asymmetric unit"). We might also consider if it is possible to decouple the selection of atoms for viewing, and selection for displaying NMR parameters. This connects with #12

[jkshenton]

It seems that the selection controls:

CLICK to select an atom/element/etc.
SHIFT+CLICK to add to the current selection
CTRL+CLICK to add or remove (XOR) from the current selection

work for each selection mode (i.e. even for 'select molecule'), so manual selection of molecule(s) in the asymmetric cell should be possible. I also see that the Report File generated for the MS data depends on the atom/molecule selection, so getting the 'distinct chemical shifts in the solid-state NMR spectrum' should be possible that way.

Indeed it might be useful to add a 'select asymmetric unit' option though, for convenience.

[dch0ph]

This is a tricky area. The starting CIF is defined in terms of an asymmetric unit. This is not guaranteed to be defined in terms of connected molecules, although this will usually be the case for molecular solids, since the software tools generating the CIF files will generally be presenting structures defined in terms of molecules (and associated labelling).

A labelled magres file contains sets of atoms with the same CIF label + an index. If you have no atoms at special positions (generally true for molecular solids), then the index can be used as a proxy for different asymmetric units. This in turn would normally give you a complete molecule (or >1 if Z' > 1). It would certainly be a valid selection to "show me the atoms with index 1".

If the magres file is unlabelled, there is no ASU information. You could try to bodge this on retrospectively by looking for runs of identical isotropic shieldings and hence auto-detecting Z', and generating labels C1, C2, etc. + ASU index. But at that point I think it would be better to retrospectively add the CIF labels to the magres prior to loading into MV [I have a script which tries to do this.]