Внутридоплеровские резонансы, обусловленные фотоионизацией атомов в тонких газовых ячейках

By analogy with the well-tested method of high-resolution spectroscopy in thin gas cells for the processes of optical pumping of atoms, this work shows the possibility of detecting narrow sub-Doppler optical resonances caused directly by straight photoionization of atoms (or molecules) in such cells. The structure of the established nontrivial resonances substantially depends on the probability of photoionization of atoms and dimensions of such a cell, the internal thickness of which is many times smaller than its diameter. Of particular interest is the broadening of the considered sub-Doppler resonances, which is determined directly by the photoionization cross section of atoms and the intensity of radiation causing ionization. Under certain conditions, such photoionization broadening can be measured experimentally with high accuracy, as a result of which it is possible to obtain new important information about ionization processes in atoms and molecules.

An Electric Field–Based Approach for Quantifying Volumes and Radii of Chemically Affected Space

Chemical shape and size play a critical role in chemistry. The van der Waal (vdW) radii, a familiar manifold used to quantify size by assuming overlapping spheres, provides rapid estimates of size in atoms, molecules, and materials. However, the vdW method may be too rigid to describe highly polarized systems and chemical systems that stray from spherical atomistic environments. To deal with these exotic chemistries, numerous alternate methods based on electron density have been presented. While each boasts inherent generality, all define the size of a chemical system, in one way or another, by its electron density. Herein, we revisit the timeless problem of assessing sizes of atoms and molecules, instead through examination of the electric field produced by them. While conceptually different than nuclei-centered methods like that of van der Waal, the field assesses chemically affected volumes. This approac

Dancing to the physics tune

British artist Geraldine Cox has created Elemental Dances – a series of videos that explore the nature of atoms and molecules through dance.