From: Ramya Gamini (ramyabhargavi_at_gmail.com)
Date: Wed Jun 10 2009 - 14:01:28 CDT
[u cm-2] should mean in units of cm-2
frequency = (1/2*pi) (k/m)^(1/2)
frequency = C (velocity of light) /wavelength (in cm-1)
k is the force constant
m is the reduced mass
k = cm-2* 4*pi^2*C^2*m
[4*pi^2*C^2*m] with 'C' and 'm' in appropriate units should tally the
and, may be you have a typo but the other unit should be kcal mol-1 A-2 and
not kcal mol A-2.
hope this helps.
On Wed, Jun 10, 2009 at 12:08 PM, Kamilla Kopec <ozero22_at_yahoo.co.uk> wrote:
> Apologies as this is pretty off-topic
> - has anybody come across units of [u cm-2] before for bond stretch force
> constants? I would like to convert a literature force constant quoted in u
> cm-2 to kcal mol A-2 for comparison with one I am using in "charmm22 with
> NAMD". My dimensional analyses have failed to produce a meaningful
> conversion factor - could someone confirm that u cm-2 is a bonafide force
> constant unit?
> Many thanks....
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