My guess is five-two-S-one-over-two. Any suggestion is appreciated. Thanks.
We usually pronounce your "one-over-two" as "one-half".
In what branch of science does this expression come from?
Absent further details, I'm tempted to say ##5^2## is pronounced "five squared".
I believe this is from the so-called term symbol for the state specification of many-electron atom.
The 5 is not squared, 5 and 2 have different meanings.
See here for example
I think pronunciation is not really relevant. You don't communicate these things verbally.
Why is there a 5 in front? As far as I know, the term symbol shouldn't have a 5 in front.
I thought that the 5 is out of place too.
But that link seems to suggest a quantum number n that goes in front.
That's indeed uncommon, but probably that indicates that the valence shell, which is the only one incomplete, corresponds to n=5.
Separate names with a comma.