Coordinates isoinertial

Although we have described the theory in terms of taking the reaction path as the MEP in isoinertial coordinates, this can be generalized to arbitrary paths by methods discussed elsewhere [41], The treatment of the reaction coordinate at geometries off the reaction path also has a significant effect on the results one can use either rectilinear [34, 37-39] or curvilinear [40, 42] coordinates for this pur-... 

A convenient choice of the reaction path is the MEP in isoinertial coordinates, because by construction the gradient of the potential V(s,u) is tangent to s and there is no coupling between s and u through second order. Therefore the potential can be conveniently approximated by... 

To carry out a VTST calculation, one first defines a reaction coordinate s. In our work we define this as the union of the paths of steepest descents from the saddle point (which is the conventional transition state) towards reactants and towards products, where these paths are computed in an isoinertial coordinate system [12], e.g., normal coordinates of the saddle point [12a,12d,12e]. (An isoinertial coordinate system is any system in the... 

It takes a diagonal mass tensor which is then invariant to any subsequent unitary coordinate transformation.Truhlar describes these as "isoinertial coordinates. The mass-weighting transformation does not necessarily introduce units of mass into the coordinates. Each coordinate can be re-scaled, if desired, to some unit mass... 

It can be shown that all isoinertial coordinates can be obtained from one another by uniform scaling and an orthogonal transformation. Therefore, the MEP is the same in all such coordinate systems. This MEP is sometimes called the intrinsic reaction coordinate or IRC. ... 

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