Yes you can create a separate PST file or you can call it Local pst file for saving Contacts and Calendars in it.
A. Create a local pst file:
1. Go to File, Account Settings, Data Files tab
2. Add a new data file
3. Click Add, type in a name for the pst file
4. Set it as Default data file
5. Set the data file as default
6. Close Outlook and reopen it
B. Move Contents from the ‘(This Computer only)’ folder to the folder in the *.pst file:
1. Switch to the Calendar (This Computer only) folder
2. Go to the View tab, select Change View
3. List views
4. Switch to a List view
5. Select All and move or drag the appointments to the new calendar folder
6. Repeat the steps above for Contacts, Tasks, and Notes if you have contents in those folders.
C. Remove the (This Computer only) folders from the IMAP data file
1. Close Outlook.
2. Open Windows Explorer, type %localappdata%\microsoft\outlook in the address bar
3. Delete the IMAP ost file
4. Restart Outlook
Now your local PST file is created where you can save your calendars and contacts.