In the “acknowledgments” section at the end of a paper, I currently have a sentence saying:
The authors thank Bob Johnson for discussions and insightful comments
However, I wonder: Bob’s full name is Robert Z. Johnson, he is a professor and a fellow of the Royal Society. Should his title be used? What about post-nominal letters? And middle initial? Finally, is it “Bob” or “Robert”?
I initially went with “Bob Johnson”, because that’s how everyone calls him (heck, his academic webpage is title “Bob Johnson”!). But is that appropriate?
In general, when in doubt, you should use the name of the author as it appears professionally. If the person in question publishes under a particular name, you should use that. The only exception is if you and the author have an existing relationship outside of this, in which case it is appropriate to use a less formal name.
You do not normally need to include honorifics ("Prof.", "Dr.", etc.) unless specifically asked to do so.
This leads to the final point: if you have any questions about how someone should be credited in an acknowledgment, ask. They'll generally be more than cooperative.