vibrational mode calculation

[sayantanu]

Dear ATK users,
In the following link it has been shown that H2 has six modes, but we know H2 has only one vibrational mode and others are translational and rotational mode. How can we know which one is which type of mode???

https://docs.quantumwise.com/tutorials/inelastic_electron_spectrometry_au_h2_au/inelastic_electron_spectrometry_au_h2_au.html

[Ulrik G. Vej-Hansen]

It sounds like you are mixing the behavior of H2 in gas phase and H2 bonded to electrodes. When it is bonded, as is the situation in the tutorial,  the translational and rotational modes will be frustrated and can all be considered as vibrational. the classification done in the tutorial is simply visual, I believe.