THEORETICAL TREATMENT OF EXCITED ROTATION-VIBRATION STATES IN VAN DER $WAALS^\dag$ MOLECULES

Author Institution: Department of Chemistry, Harvard UniversityUse of the Born-Oppenheimer angular-radial separation method foe calculating ground state properties of atom-diatomic complexes has been extended to calculating properties of the excited rotation-vibration states of these complexes. This was accomplished by changing the basis set from a 2-dimensional to a full 3-dimensional description of the complex, as well as including terms in the Hamiltonian that were not retained in the ground state treatment. Careful comparison was made to close coupling calculations as various approximations were removed, and their effects on the ground and excited state properties were noted. The importance of such a fast, low-cost calculational method is examined in light of its expected use in the analysis of rotation-vibration spectra of molecules with large amounts of internal motion