Dear all,

Hope you have a good day.

The Reaction Kinetics task, which is contained in the DMol3, is related to the reaction rate as far as I know.

After the calculation is done, the study table is printed out with the Arrhenius constant in it.

I figured out the difference between the standard equation and the modified equation, but still don't know which constant(A) I should use.

First, I think, the standard equation would be:

k = A*e^(-Ea/RT)

The modified equation would be:

k=A*(T/T0)^n *e^(-Ea/RT)

It would be helpful if someone check whether the above difference was correct.

Secondly, there are a total of four A values(Arrhenius constant) printed out in the study table.

Two for the forward reaction and the other for the backward reaction, standard and modified equations each.

Here, the problem is, that A has different units for the forward and backward.

The forward has its unit for 1/s and the backward for cm3/molecule/s.

Again, as far as I learned before, the A means the collision frequency in the chemical reaction, so it makes sense for the backward unit.

However, for A unit of the forward reaction makes me confused.

What do they mean for the four different A constants?

Thank you always.

Best regards,

Rakhoon Choi