QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: Sabyasachi Sen on July 16, 2016, 13:56
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I furnish below part of the result obtained with a IETS run;
------------------------------------------------------------------------------+
| Vibrational Mode Report |
| ---------------------------------------------------------------------------- |
| K-point = [0.000000, 0.000000, 0.000000] (fractional) |
+------------------------------------------------------------------------------+
Mode index Energy Wavenumber
+------------------------------------------------------------------------------+
Mode 0: -3928.83 meV -31688.14 cm^-1 (eigenmode available)
Mode 1: -3478.62 meV -28056.95 cm^-1 (eigenmode available)
Mode 2: -3084.02 meV -24874.30 cm^-1 (eigenmode available)
Mode 3: -2952.32 meV -23812.08 cm^-1 (eigenmode available)
Mode 4: -2084.22 meV -16810.40 cm^-1 (eigenmode available)
The problem is there are altogether 82 modes available. Energies are probably phonon energy. In the output it is written 'eigenmode available'; but which vibartional mode is important would be understood if numerical data such as intensity of vibration/vibational amplitude is known. Kindly, inform me how to get the intensity of various vibrational mode so that we can make transmission spectrum calculation only on those significant modes.
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I am not sure how to define the intensity of a vibrational mode, but the vibrational amplitude depends on temperature. So I think it is not an altogether simple matter to define a measure for the relative importance of vibrational modes.
On another note: It seems curious that your vibrational energies/wavenumbers are so large and negative. This usually implies that the structure was not properly geometry optimized.