Atom lab also repeatedly involved with source of molecules (3,6)
I believe the answer is:
los alamos
'atom lab' is the definition.
The definition suggests a singular noun which matches the answer.
'also repeatedly involved with source of molecules' is the wordplay.
I cannot really understand how this works, but
an anagram of 'also' is 'losa' which is present in the answer.
'of' could be 'o' and 'o' is found in the answer.
The remaining letters 'lams' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for los alamos that I've seen is " research centre".)