Dear @Mariangela ,
To find and show hydrogen bonds you can use the Hydrogen Bond Finder Extension. It allows you to find all H-bonds in the selected system or between two systems, for example, between a receptor and a ligand.
To find/show H-bonds between a receptor and a ligand, perform the following steps (see the gif at the end):
in the
Hydrogen Bond Finder Extension click on "...in the current selection and the system";
select the receptor in the Document view and in the
Hydrogen Bond Finder click Set;
set the Settings of the
Hydrogen Bond Finder if necessary;
now, select only the ligand in the Document view and in the
Hydrogen Bond Finder click Add hydrogen bond visual model
Now you should have a new visual model in the Document view. If you select it, you can modify its options in the Inspector.
See an example below:
