It is unfortunate that they are no longer on that campus.
I recommend contacting the university to see if they have any records of ANYTHING pertaining to the organization or some of the members whose names you remember.
I assume it was a local so there wouldn't be a larger entity to contact. (There's another Sigma Phi Nu that was founded in 1996)
“Everyone has a sense of humor. If you don't laugh at jokes, you probably laugh at opinions.” ~ Criss Jami
What the world needs is more geniuses with humility, there are so few of us left.