There is a new test build of VMD for Catalina.

Latest version (May 8) Updated modeling plugins updated for Tk 8.6 (grid vs. pack corrections)

VMD is a molecular visualization program for displaying, animating, and analyzing large biomolecular systems using 3-D graphics and built-in scripting.

There are details of many other scientific applications under Catalina here

Scientific Applications under Catalina: Update 13