Back to
Animations.
Back to CH2O Vibrations
| ===> |
Using PM6, the third vibrational mode of formaldehyde, an A1, occurs at 1351cm-1. This corresponds to a vibrational period of 1/(1351x3x1010) seconds, or 24.7x10-15 s, or 24.7 femtoseconds. This is the scissors vibration, and is very unsymmetrical. In this simulation, each frame represents 0.2 fs, and the display is 50 frames per second, so each second represents 10fs. One complete vibration takes about 2.5s From this it follows that the period for a vibration is about 25.0 fs and has a frequency of 1/(3x1010x25.0x10-15) cm-1 or 1333 cm-1 in accordance with the results of the vibrational calculation. Only one complete vibration is shown, as if the simulation were to be run further, the calculated trajectory of the normal coordinate would rapidly deviate from the correct path, and the results would be inaccurate. |
Data set used by MOPAC:
irc=3 drc cycles=81 t-priority=0.2 Formaldehyde O 0.00000000 +0 0.0000000 +0 0.0000000 +0 -0.4225 C 1.21074828 +1 0.0000000 +0 0.0000000 +0 1 0 0 0.2366 H 1.09713884 +1 122.0336155 +1 0.0000000 +0 2 1 0 0.0929 H 1.09712655 +1 122.0249758 +1 180.0000000 +0 2 1 3 0.0929