Knowledge Bank

The microwave spectrum of tetrahydropyran has been investigated in the frequency region 8-40 Gc. The rotational constants for the chair form are $A=4673.5,B=4495.0$ and $C=2601.3$ Mc, in the ground vibrational state. The spectrum of the molecule in an excited vibrational state has also been observed for which $A=4689.9,B=4494.2$ and $C=2608.7$ Mc. The dipole moment of the molecule in the ground state has been determined to be 1.74 D.