Wilson vectors

GUEST AND WILSON Vector Processors in Quantum Chemistry... 

The expressions for the s. are available from molecular vibration theory, for the common internal coordinates of bond-stretch, angle-bend, and torsion. As described earlier, s. points in the direction in which a displacement of particle i produces the greatest change in Equation [77] provides a physical picture of the SHAKE displacements for internal coordinate constraints. In the language of Wilson vectors, the singularity condition for internal coordinate constraints takes the form... 

In Eq. [79], time step and in particular at the preceding time step t. Replacing [V (r fe]( o) by the Wilson vectors and neglecting all nonlin-... 

Figure 1 SHAKE displacements for angle-bend constraint. The displacements are shown relative to the molecular configuration at the preceding time step t and have the (negative) directions of the Wilson vectors for an angle-bend internal coordinate. The displacements of the end atoms are perpendicular to the bond directions at and the displacement of the apex atom points in the direction of the sum of their Wilson vectors.

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