MDRzx616

H+H2 system

The transition state can be determined by looking at the surface plot. The settle point is believed to be the place where Transition state is located at (0.40,0.40, -97). This is considered to be the transition state because the partial derivative of both AB and BC distances give a minimum, and the partial derivative of reaction coordinate and energy give a maximum. This is confirmed by checking whether the place is inside the reaction coordinate. Since r1=r2, this place is believed to be the transition state.

When r1=r2, with p1=p2=0 (since the gradient is 0), this is where TS is located. By adjusting proper values, r=0.908. This is backed up by looking at the internuclear distance vs time graph where BC and AC distance does not change over time, only atomic vibration occurs. When there is no oscillation within molecules and between atoms, TS is achieved.

When MEP calculation is done, one will see that the line becomes smoother than Dynamic in surface plot, in which molecules are believed to oscillate. Therefore one can conclude that MEP is suitable for providing a macro picture of a reaction whereas the Dynamic provides a detailed behaviors of atoms in a reaction.

Intermolecular momenta vs time: for MEP the line becomes a flat line compare to Dynamic where lines are oscillating;

Intermolecular distance vs time: for MEP the graph becomes a curved line compare to dynamic where they are straight lines with positive gradients.

Table

p1	p2	Total Energy	Reactive/Unreactive
-1.25	-2.5	cell	cell
-1.5	-2.0	cell	cell
-1.5	-2.5	cell	cell
-2.5	-5.0	cell	cell
-2.5	-5.2	cell	cell