Ab initio investigation of the simultaneous motion of protons in the hydrogen bonds in the cyclic dimer of formamide
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Abstract
The simultaneous motion of protons in interacting H-bonds plays an important role in biochemistry. By means of the simple example of the cyclic dimer of formamide some significant properties of the simultaneous motion of protons are discussed.
Starting from the calculations of Dreyfus, Maigret, and A. Pullman [9] an energy surface as well as a surface of dipole moment for the linear motion of the two protons is calculated point by point using a selfwritten program of the SCF-MO-LC (LCGO)-method and using a Gaussian basis set of intermediate size.
The resulting surface of total energy is further used to determine the states of vibration of the simultaneous motion of the protons. Whereas the surface of dipole moment is used to compute the relative transition intensities. These spectroscopic properties are finally used to find a criterion for estimating the kind of motion - mainly correlated or mainly independent.
Key words
Coupled H-bonds Cyclic formamide dimer Proton motion Computed vibrational spectraPreview
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