Potential Function Model of Hydrogen Bonds. II

Abstract

Potential Function Model of Hydrogen Bonds 921 pear as if two endothermic peaks are occurring.This explanation is consistent with the observation that the small peak occurred in the pattern of CuS04-5H20 in Fig. 1 only when the doublet appeared, that is, only when liquid formed in the sample and only at high rates of temperature rise.18 Since the sample wells in this work are very small, thermal gradients are reduced to a minimum. In order to establish an appreciable gradient high heat-(13) Taylor and Klug* observed several small peaks prior to dehydration which they attributed to second-order transitions in CuSOrSHjO. These were observed at sensitivities much higher than those used in the present work and are apparently not the same as the anomalous peak described above.ing rates are necessary.The results of this investigation emphasize precautions which are necessary in the interpretations of some differential thermal analysis measurements.

Two-dimensional infrared spectroscopy of isotope-diluted ice Ih

“…With this observation we argue that there must be other mechanisms responsible for the broadening of the 1-2 transition, possibly in addition to the suggested Fermi resonance, 39 since the OD vibration is no longer in resonance with the second overtone of the HOD bending mode. We show that a full non-adiabatic treatment of the Lippincott-Schroeder potential, which has been widely used to explain spectroscopic and structural features of hydrogenbonded crystals, 43,44 can qualitatively explain all experimental observations.…”

“…We explain the experimental results in the framework of the Lippincott-Schroeder model 43 43,44,[52][53][54] The detailed outcome of the calculation does depend on these parameters, as such we stress that we do not consider the results to be quantitative. We will nevertheless see that the Lippincott-Schroeder potential can qualitatively reproduce the 2D IR response.…”

“…63 The Lippincott-Schroeder model was originally designed to explain the energetics and spectroscopy of hydrogen bonded crystals, in particular the strong dependence of the OH vibrational frequency on the O· · ·O hydrogen bond length. 43, 44 Bakker and co-workers have extended the idea and applied it to pump-probe spectroscopy, which, in essence, includes higher vibrational states. They explain successfully the asymmetry of the spectral width of the 0-1 versus the 1-2 transition in the IR-pump-probe response in liquid water, 50,51 but conclude that it fails for ice Ih, 39 where this asymmetry is much more pronounced but structural disorder is less.…”

New Approach to the Problem of the Interlayer Bonding in Kaolinite

“…data and from the diffraction data showed that the former values are greater than the latter. It seems proper then to apply a model of bent Interlayer O-O distance from diffraction data after Giese and Datta (1973) according to Zyyagin's data [A] hydrogen bonds instead of the linear ones (Schroeder and Lippincott, 1957). Such a model (Fig.…”

Nucleic acid binding drugs. Some conformational properties of the anti‐cancer drug daunomycin and several of its derivatives:

“…Computation of the hydrogen-bond stabilisation by standard methods [25] gives an associated energy of 1.7 kcal/mol, which more than offsets this difference. Molecular model-building shows that the @( 1) = 93" and 124' conformations can both fit into a DNA-binding model [7,12,13] -the maximal differences in the 011-N distances of 0.1 A are not significant.…”