On some third-order corrections to the rotation-vibration energies of polyatomic molecules

摘要: Abstract After a review of the principles for calculating higher-order rotation-vibration energies polyatomic molecules, corrective terms third order are studied. Third-order effects first considered in absence accidental resonances, and all nonvanishing diagonal nondiagonal elements that must be included matrix calculated molecules with axial symmetry, linear asymmetric molecules. The results obtained applied to study transitions J = 1 → 2 an excited state vt (lt ±1) belonging symmetry group C3v. Comparison is made microwave spectrum methylisocyanide v8 1. Next, two third-order presence resonances studied: Taylor-Benedict-Strong correction variation Fermi-resonance term quantum number J. It shown particular coefficient λl vanishes triatomic molecule, which excellent agreement experimental infrared carbon dioxide.