Schlegel projection

Hoppe, R. and Kohler, J. (1988). Schlegel projections and Schlegel diagrams— new ways to describe and discuss solid state compounds. Zeit. Kristallogr. 183, 77-111. 

Wittbrodt, J. M., Schlegel, H. B., 1996, Some Reasons Not to Use Spin Projected Density Functional Theory , J. Chem. Phys., 105, 6574. 

The author wishes to thank Jean-Marie Contreras, Camille-G. Wermuth (Prestwick Chemical, Illkirch, France), Dirk Classen-Houben and Hans-Dieter Holtje (Heinrich-Heine-Universitat Dtisseldorf, Germany) for their cooperation and support of this project. Birgit Schlegel (Heinrich-Heine-Universitat Dtisseldorf, Germany) is acknowledged for critical review of the manuscript. 

A method devised by Schlegel has seen widespread use as a part of the GAUSSIAN system of MO programs. The Hessian in the full space is updated in the smaller space spanned by the current and previous steps. The available gradients are projected into the small space and elements of the Hessian in the small space are computed according to... 

Using as an example the reactions of radical addition to a double and a triple bond, Schlegel and Sosa [15-18] have shown that the unwanted spin contamination must be removed with the aid of projection methods [19]. Thus, for the reactions H -h H + CH20t CH 0 [15], OH + C2H2 ... 

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