Asymmetric-Top Vibration—Rotation Hamiltonians

From the general molecular vibration—rotation Hamiltonian in the Nielsen—Amat—Goldsmith formulation, Hamiltonians for asymmetric-top molecules of the orthorhombic, monoclinic, and triclinic point group symmetries are deduced. These Hamiltonians are appropriate for the calculation of vibration—rotation energies to the fourth order of approximation.