FULLCHN(n) 

Description

FULLCHN is used to locate all saddle point (transition state) geometries along a reaction path between two local minima (reactant and product). This is more expensive than just CHN or CHAIN but is particularly useful for multi-step reaction mechanisms.

FULLCHN takes as input two or more geometries. Each of geometries must have the same composition and atom ordering. The first geometry is taken as the reactant (starting point) and the last geometry is taken as the products (ending point). If OPTIL is specified then the first geometry is optimized to a minima by TRUSTE and if OPTIR is specified then the last geometry is optimized to a minima. (OPTILR or OPTIRL causes both geometries to be optimized.) If more than 2 geometries are specified, then they are taken as intermediates between the reactants and the products. The initial number of nodes is set to “n.” If FULLCHN is specified without the “n” then the initial number of nodes is set to 5. (See Chapter 8, CHN Methodsfor more details.)

If FORCE or LFORCE is also specified, then IR frequencies will be computed for each extrema on the chain path. In the case of FORCE, thermodynamic properties will be computed along with the IR frequencies.

See also:

CATCHTS, CHN, TS, LTRD.