Under rotational spectroscopy, this molecule has two Q branches, and its energy splits by 23.8 GHz.
This was the first molecule modelled by a potential including a hyperbolic secant raised to the fourth power, which is named for Manning. The HCTH/407+ gradient approximation was developed to model the unusual dimer of this molecule, which has a G144 symmetry group and was once thought by Nelson, Fraser, and Klemperer to have a cyclic structure. Under rotational spectroscopy, this molecule has two Q branches, and its energy splits by 23.8 GHz. Feynman's lectures introduce the (*) Rabi formula with the example of this system, which is the characteristic compound modelled by a double-square well potential. It is the simplest member of the C3v point group. One atom tunnels through the plane of the other atoms in this molecule's umbrella transition, which Charles Townes used as a basis for the first maser. For 10 points, name this lightest trigonal pyramidal molecule.
This was the first molecule modelled by a potential including a hyperbolic secant raised to the fourth power, which is named for Manning.
ammonia [or NH3]