Ammonia and Time

Ammonia potential V(x) for movement of N atoms:

The H atoms define the level in ammonia. If nitrogen atom is situated first on the right side of potential barrier then there is a chance that it can overcome the barrier and finds itself on the left side potential barrier (It's because N and H atoms move in opposite directions, moreover the N atom divergence is smaller than that of H atoms).

The movement of N atom consists of left and right side vibrations plus much more slower movement between left and right zones of potential. The frequency of this movement is as follows 2,3789 · 1010 Hz (for the lowest state) and it was the way to measure the correct time! It was time standard for atomic clocks. But now time is measured by the following way.
For time-independent (stationary) states the energy levels are easily splitted. H atoms on the right side ''feel' the potential on the right side. We will get acquainted with interesting and extremely useful description which is useful for chemical analysis in the next chapter.

Potential and energy levels for the inverse movement in NH3.

Level | cm−1 | eV
3 a | 2681 | 0,3547
3 s | 2380 | 0,2950
2 a | 1910 | 0,2367
2 s | 1597,4 | 0,1980
1 a | 989,00 | 0,1222
1 s | 950,16 | 0,1178
0 a | 0,79 | 9,84 · 10−5
0 s | 0,00 | 0,00
Vibrational levels for axial movement of N in molecule NH3 relative to the ground state.