Thank you Mark.
On Jul 8, 2011, at 11:17 AM, Mark Abraham wrote:
On 9/07/2011 1:36 AM, Marcelo A. Carignano wrote:
Hi all,
Stochastic dynamics is described in section 3.8 of the Manual (v.
4.5)
Equation 3.108 is dimensionally incorrect, or at least I cannot
understand it.
Left hand side is a force,
Specifically, mass * length * time^-2. Note that (d^2 r)/(d t^2) is
(d/dt) (d/dt) r, which makes the dimensionality more clear.
and the first term on the right hand side has a missing length in
the numerator to be a force.
It has a missing length dimension to be an *energy* :-)
you are of course right, I should not work in the mornings!
This is according to the definition of xi, right below the
equation, as having units of 1/ps.
Brownian dynamics, described in section 3.9, also has a problem
(again, in my opinion)
gamma is defined as mass/xi, but it is using gamma=mass*xi that we
can recover the two terms of the SD case
(still with the wrong dimensions)
Seems OK to me, similarly.
But what is gamma? mass*xi (still is before noon over here)
If so, the manual has a missprint.
Mark
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