[tex]K=V\Lambda U^T[\tex]<br />
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K is formed by summing over i the outer products of the coordinate vectors of atom i in the first and second geometry. (i follow the method described at http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/MARBLE/high/pose/least.htm" )<br />
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I.e K depends on atomic coordinates, and so do U and V.<br />
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I require the derivative of each element of R with respect to atomic coordinate. (The rotation matrix is used in an energy approximation and I need analytic forces)<br />
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Any answers or hints much appreciated.[/tex]