Jon Baker Peter Pulay Efficient geometry optimization of molecular clusters. 69-76 2000 21 Journal of Computational Chemistry 1 http://dx.doi.org/10.1002/(SICI)1096-987X(20000115)21:1<69::AID-JCC8>3.0.CO;2-G db/journals/jcc/jcc21.html#BakerP00