The key to ion beams' polarisability

July 17, 2013, Springer

Polarisability determines the force with which an inhomogeneous external electric field acts on the ions of an ion beam. However, it can be quite tricky to obtain accurate values for this force. Now, two German theoretical chemists, Volker Koch from Bielefeld University and Dirk Andrae from the Free University Berlin, have devised formulas providing the polarisability of atomic ions as a function of their total charge number. Their findings, about to be published in EPJ D, have implications for many applications, ranging from the use of ion beams for research purposes or as a source for dopant atoms in semiconductor manufacturing to the modelling of planetary and stellar atmospheres.

Being a characteristic quantity of an atom's or ion's electronic state, the polarisability of or ions with several electrons had been difficult to obtain to date because simple equations for it were not available. Most previous theoretical studies of polarisability focused on individual atoms, or early members of series with a constant number of electrons, so called isoelectronic sequences. The electron numbers were usually small, and closed-form expression for the polarisability was never provided. A single exception to this situation were the formulae related to the so-called Stark effect in hydrogen-like atoms derived by Austrian physicist Erwin Schrödinger and Russian-American physicist Paul Epstein, back in 1926.

In their study, the authors used a numerical method to calculate the energy of atoms and ions of a given isoelectronic sequence under various strengths of an external electric field. This numerical approach makes it possible to derive the polarisability of atoms with small to large electron numbers using conventional techniques of numerical analysis.

Koch and Andrae thus established a rational function for each isoelectronic sequence to represent the polarisability data previously established with the numerical method. In addition to generalising previous findings made on hydrogen-like atoms, this research also provides a reference for future use.

Explore further: Magnetic shielding of ion beam thruster walls

More information: European Physical Journal D 67: 139, DOI 10.1140/epjd/e2013-40191-5

Related Stories

Magnetic shielding of ion beam thruster walls

February 13, 2013

Electric rocket engines known as Hall thrusters, which use a super high-velocity stream of ions to propel a spacecraft in space, have been used successfully onboard many missions for half a century. Erosion of the discharge ...

New method to generate Laughlin states with atomic systems

July 3, 2013

In 1998, the Nobel Prize in Physics was conferred to the discovery of a new type of quantum fluid with fractional charge excitations, known as Laughlin state. The production of this quantum state, which explains the behaviour ...

New methods for ion cooling

November 26, 2012

Among the most important techniques developed in atomic physics over the past few years are methods that enable the storage and cooling of atoms and ions at temperatures just above absolute zero. Scientists from Bangalore ...

Eavesdropping on lithium ions

July 8, 2013

(Phys.org) —Lithium ion batteries are at the energetic heart of almost all things tech, from cell phones to tablets to electric vehicles. That's because they are a proven technology, light, long-lasting and powerful. But ...

Elucidating energy shifts in optical tweezers

May 8, 2013

A small piece of paper sticks to an electrically charged plastic ruler. The principle of this simple classroom physics experiment is applied at the microscopic scale by so-called optical tweezers to get the likes of polystyrene ...

Recommended for you

Walking crystals may lead to new field of crystal robotics

February 23, 2018

Researchers have demonstrated that tiny micrometer-sized crystals—just barely visible to the human eye—can "walk" inchworm-style across the slide of a microscope. Other crystals are capable of different modes of locomotion ...

Researchers turn light upside down

February 23, 2018

Researchers from CIC nanoGUNE (San Sebastian, Spain) and collaborators have reported in Science the development of a so-called hyperbolic metasurface on which light propagates with completely reshaped wafefronts. This scientific ...

Recurrences in an isolated quantum many-body system

February 23, 2018

It is one of the most astonishing results of physics—when a complex system is left alone, it will return to its initial state with almost perfect precision. Gas particles, for example, chaotically swirling around in a container, ...

Seeing nanoscale details in mammalian cells

February 23, 2018

In 2014, W. E. Moerner, the Harry S. Mosher Professor of Chemistry at Stanford University, won the Nobel Prize in chemistry for co-developing a way of imaging shapes inside cells at very high resolution, called super-resolution ...

Hauling antiprotons around in a van

February 22, 2018

A team of researchers working on the antiProton Unstable Matter Annihilation (PUMA) project near CERN's particle laboratory, according to a report in Nature, plans to capture a billion antiprotons, put them in a shipping ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.