That's right, Vassar has an institutional repository! It's called Vassar Scholarship and it collects, preserves, and provides access to scholarly works created at Vassar. Vassar Scholarship also serves a publishing space for student research, such as capstone projects.
Institutional repositories use a Green OA business model. The items deposited in an institutional repository can be pre-prints or post-prints. Most journals allow pre-prints to be posted even if they own the copyright to the finished article.