Biomedical subjects

A D Buckingham

Publications and source records attributed to A D Buckingham.

4 recordsLinked to original sources

PubMed2003

New electro-optic effect: sum-frequency generation from optically active liquids in the presence of a dc electric field.

We report the observation of sum-frequency signals that depend linearly on an applied electrostatic field and that change sign with the handedness of an optically active solute. This recently predicted chiral electro-optic effect exists in the electric-dipole approximation. The static electric field gives rise to an electric-field-induced sum-frequency signal (an achiral third-order process) that interferes with the chirality-specific sum-frequency at second order. The cross-terms linear in the electrostatic field constitute the effect and may be used to determine the absolute sign of second- and third-order nonlinear-optical susceptibilities in isotropic media.

Electromagnetic Fields↗

PubMed2001

Time reversal and molecular properties.

Chemists regularly exploit point group symmetry in their analyses of molecular structure and properties but they rarely utilize time reversal symmetry. The time reversal operator T reverses the momenta and spins of all particles in a system and distinguishes properties which are even under T, such as the electric dipole moment, from those that are odd, such as the magnetic dipole moment. We review the role of T in quantum mechanics and discuss its application to the properties of molecules in electric and magnetic fields. Among the properties considered are natural and magnetic optical activity, magneto-chiral effects, antisymmetric Raman scattering, optical NMR and ESR, chirality, and absolute enantioselection.

Journal Article↗

PubMed1998

Molecules in optical, electric, and magnetic fields: a personal perspective.

Physical chemistry and theoretical chemistry have advanced over the past 50 years from being largely qualitative to having a mature status based firmly on the principles of quantum and statistical mechanics. My interest in the chemical elements and their compounds has prompted me to learn more about the nature of matter through the measurement and interpretation of optical, electric, and magnetic properties of molecules. In addition to holding intrinsic interest, such properties tell us about charge and current distributions and form the basis of electro-optics, magneto-optics, and nonlinear optics. They also help us understand the nature and strength of long-range intermolecular forces, the hydrogen bond, and molecular biology-topics that are apparently forever young.

Journal Article↗

PubMed1975

Intermolecular forces.

The nature of molecular interactions is examined. Intermolecular forces are divided into long-range and short-range components; the former operate at distances where the effects of electron exchange are negligible and decrease as an inverse power of the separation. The long-range interactions may be subdividied into electrostatic, induction and dispersion contributions, where the electrostatic component is the interaction of the permanent charge distributions and the others originate in the fluctuations in the distributions. Typical magnitudes of the various contributions are given. The forces between macroscopic bodies are briefly considered, as are the effects of a medium. Some of the manifestations of molecular interactions are discussed.

Chemical Phenomena↗