Units of frequency obtained in Dynamical Matrix calculations

[kng208]

Hi,

I was just wondering why is the Unit of frequencies obtained from the DynMat calculations in cm ^-1?
Shouldn't it be in units of time ^-1, ie second ^-1 or Hz ?

Thanks..

[graeme]

Chemists like wavenumbers; use the speed of light to convert.

[kng208]

Oh, I got it. Thank you very much.

However, two different definitions of wavenumbers are there.
How is it defined here? Is it 1/wavelength, or (2*pi)/wavelength ?

[graeme]

1/wavelength; consistent with almost all spectroscopy data.