Article: Author information when occupation has changed
This may be specific to journal, research area, whatnot. However, in a recent edition of Applied Physics Letters one finds in the author list:



The "2" corresponds to an institute in the affiliations list (other authors have other affiliations) where the author was at during the work. 

The "a)" links to:



Followed by the new address for that person. 

Other uses for footnotes include email addresses and apportioning credit.

This is how it was done some 25 years ago when I last changed institutions.