The concept of characterizing normal vibrational modes l in terms of internal vibrational modes v typical of molecular fragments or structural subunits is n developed. Essential for this concept is the amplitude A A that provides the basis for a n quantitative comparison of modes l and v and, by thi
A new way of analyzing vibrational spectra. IV. Application and testing of adiabatic modes within the concept of the characterization of normal modes
β Scribed by Zoran Konkoli; J. Andreas Larsson; Dieter Cremer
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 481 KB
- Volume
- 67
- Category
- Article
- ISSN
- 0020-7608
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β¦ Synopsis
The CNM characterization of normal modes method for extracting chemical information out of vibrational spectra is tested for vibrational spectra of molecules with relatively strong or relatively weak coupling between internal vibrational modes. Symmetry, parameter set stability, and frequency uncertainty tests are applied to check whether internal vibrational modes, internal mode frequencies, and amplitudes A A comply with symmetry, are independent of the set of internal parameters used to n n describe molecular geometry or fulfill a Lorentzian correlation between amplitudes A A n and frequency differences β¬ s y . In all cases considered, amplitudes A A n n n based on adiabatic internal modes and mass or force constant matrices as metric O are superior to any other definition of amplitude. They represent the basic elements of the new CNM method that leads to chemically reasonable results and presents a new way of extracting chemical information out of vibrational spectra. A number of deficiencies of Ε½ . the potential energy distribution PED analysis is discussed.
π SIMILAR VOLUMES
A new way of analyzing measured or calculated vibrational spectra in terms of internal vibrational modes associated with the internal parameters used to describe geometry and conformation of a molecule is described. The internal modes are determined by solving the EulerαLagrange equations for molecu