Biomedical subjects

W K Schroll

Publications and source records attributed to W K Schroll.

3 recordsLinked to original sources

PubMed1991

Low-frequency parameterization of hydrogen bonding.

We review the model of the hydrogen bond developed by Lippincott and Schroeder and discuss the frequency range in which it is valid, specifically in the optical and near infrared range. We then show why and how to modify the Lippincott and Schroeder formulate to apply to the far infrared and lower ranges. The contrasts between the old and modified systems, particularly with respect to the effective force constants are worked out and plotted for an example.

DNA↗

PubMed1990

Modeling hydrogen bonds in three dimensions.

The effective potential between two hydrogen bonded atoms is calculated on the basis of the Lippencott-Schroeder bent bond model, taken to be a typical model interaction. We differ from other calculations in that the minimum energy configuration for the proton is treated adiabatically, its position being recomputed at each value of the larger atoms separation. We find the typical hard core to have been a consequence of an artificial restriction of the proton to a fixed angle with the larger atom axis, basically a one-dimensional assumption. Free to move in three dimensions, the proton is squeezed off the axis as the separation narrows, and the hard core feature is gone. Depending on the degree of bond bending, the anharmonicity of the bond may be diminished, eliminated, or even reversed.

Computer Simulation↗

PubMed1989

Phonon interpretation of inelastic neutron scattering in DNA crystals.

The calculated spectrum of longitudinal compressional waves on DNA polymer chains is shown to be in excellent agreement with recently performed inelastic neutron scattering measurements in hydrated, oriented DNA crystals. This opens up a previously unexplored frequency regime of DNA science and establishes the validity of the phonon extended wave description of DNA elementary excitations in this region.

DNA↗