PSI is a computational chemistry package originally written by the research group of H. F. Schaefer III. Primary development of PSI3 has been carried out by Daniel Crawford, David Sherrill, Edward Valeev, and Rollin King.
davidnbrooks: RT: @generatorx Daniel Brown: On Growth and Form, ongoing work on computational flowers http://ow.ly/Ohoc; http://ow.ly/Ohpb // Fantastic