The calculations of accurate normal co-ordinates—I

摘要: The calculation of accurate and reliable vibrational potential functions normal co-ordinates is discussed, for such simple polyatomic molecules as it may be possible. Such calculations should corrected the effects anharmonicity resonance interactions between states, fitted to all available information on isotopic species: particularly frequencies, Coriolis zeta constants centrifugal distortion constants. difficulties making these corrections, use observed data are reviewed. A programme Ferranti Mercury Computer described by means which harmonic vibration frequencies co-ordinate vectors, factors can calculated, from a given force field G-matrix elements, etc. has been used up 5 × secular equations single output results takes approximately l min; readily extended larger determinants. best methods using possibility reversing direction discussed. The applied calculating possible function methane molecule, data.