Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Europhysics news

Ion Coulomb crystals: from quantum technology to chemistry close to the absolute zero point

Olivier Dulieu, Stefan Willitsch

Published Mar 1, 2017• 2 citations
Publisher

Abstract

Ion Coulomb crystals are ordered structures of atomic or molecular ions stored in ion traps at temperatures close to the absolute zero point. These unusual “crystals” form the basis of extremely accurate clocks, provide an environment for precise studies of chemical reactions and enable advanced implementations of the technology for a quantum computer. In this article, we discuss the techniques for generating atomic and molecular Coulomb crystals and highlight some of their applications.

DOI
10.1051/epn/2017203

Related papers

Chemical applications of laser- and sympathetically-cooled ions in ion traps

Stefan Willitsch, Martin T. Bell, Alexander D. Gingell +1 more

Ensembles of cold atomic and molecular ions in ion traps prepared at millikelvin temperatures by laser and sympathetic cooling have recently found considerable interest in both physics and chemistry. At very low temperatures the ions form ordered structures in the trap also known as "Coulomb crystals". Ion Coulomb crystals exhibit a range of intriguing properties which render them attractive systems for novel experiments in chemical dynamics, ultrahigh-resolution spectroscopy and quantum-information processing. In this article we review the methods used to prepare atomic and molecular ion Coulomb crystals and discuss some recent studies in mass spectrometry, low-temperature chemistry and precision spectroscopy to illustrate their scientific potential for chemical applications. Finally, we conclude with an outlook on outstanding challenges and prospective further developments in the field.

Physical Chemistry Chemical Physics•Jan 1, 2008•146 citations

Molecules and Ions at Very Low Temperatures

Stefan Willitsch

The generation and study of 'cold' gas-phase molecules characterised by very low translational temperatures Ttrans ? 1 K is an upcoming field of research in physical chemistry which has received considerable attention over the past years. A particular interesting form of cold molecules are ensembles of cold localised cations in ion traps which form ordered structures known as 'Coulomb crystals'. The present article reviews the experimental methods used for the generation of atomic and molecular Coulomb crystals and highlights recent experiments which take advantage of their intriguing properties in order to study chemical reactions at very low temperatures with single-particle sensitivity.

CHIMIA International Journal for Chemistry•Feb 25, 2009•0 citations

Ion Coulomb crystals

Richard Claude Thompson

Ion Coulomb crystals, formed by atomic ions at low temperatures in radiofrequency and Penning ion traps, are structures that have remarkable properties and many applications. Images of Coulomb crystals are striking and reveal the crystal structure, which arises from a balance between the trapping forces acting on the ions and their mutual Coulomb repulsion. Applications of these structures range from frequency standards and quantum simulation through to measurement of the cross-sections of chemical reactions of ions.

arXiv:1411.4945•Contemporary Physics•Jan 2, 2015•77 citations

Chemistry Using Coulomb Crystals

Brianna R. Heazlewood, Heather J. Lewandowski

Laser cooling of atomic ions has long been used as a tool in physics to explore quantum entanglement for applications in quantum computing and information. More recently, laser-cooled atomic ions have been used as a platform for studying cold chemistry. Here, we describe an experimental system called a “Coulomb crystal,” where laser-cooled ions are confined in traps at sufficiently low translational energies that they form an ordered structure. We then present a range of experiments undertaken using this platform, from studies of reactions with an atomic species to reaction systems of increased complexity, involving molecular ions and neutral molecules. We also describe a few spectroscopic studies enabled by Coulomb crystals before discussing some possible future directions of the field. This is not meant to be a comprehensive review of the entire field, but rather a sampling of the types of experiments that can be performed and the knowledge gained from these studies.

ACS symposium series•Oct 27, 2021•8 citations

Spectroscopy of Molecular Ions in Coulomb Crystals

Aaron T. Calvin, Kenneth R. Brown

In this Perspective, we examine the use of laser-cooled atomic ions and sympathetically cooled molecular ions in Coulomb crystals for molecular spectroscopy. Coulomb crystals are well-isolated environments that provide localization and long storage times for sensitive measurements of weak signals and cold temperatures for precise spectroscopy. Coulomb crystals of molecular and atomic ions enable the detection of single-photon molecular ion transitions at a range of wavelengths by a change in atomic ion fluorescence at visible wavelengths. We give an overview of the state of the art from action spectroscopy to quantum logic spectroscopy for a wide range of molecular transitions from rotational sublevels separated by 10 –7 cm –1 to rovibronic transitions at 25 000 cm –1 . We emphasize how this system allows for unparalleled control of the molecular ion state for precision spectroscopy with applications in astrochemistry and fundamental physics. We conclude with an outlook of the use of this control in cold molecular ion reactions.

The Journal of Physical Chemistry Letters•Sep 13, 2018•19 citations

Ion-molecule chemistry at very low temperatures: cold chemical reactions between Coulomb-crystallized ions and velocity-selected neutral molecules

Martin T. Bell, Alexander D. Gingell, James M. Oldham +2 more

The recent development of a range of techniques for producing cold atoms and molecules at very low translational temperatures T < or = 1 K has provided the opportunity to investigate collisional processes in a new physical regime. We have recently presented a new experimental method to study low-temperature reactive collisions between translationally cold ions and neutral molecules (S. Willitsch et al., Phys. Rev. Lett. 2008, 100, 043203). Our technique relies on the combination of a quadrupole-guide velocity selector for the generation of translationally cold neutral molecules with a facility to produce ordered structures of cold ions (Coulomb crystals) by laser cooling in a linear quadrupole ion trap. The strong localisation of the ions in the trap in combination with the high sensitivity of laser-induced-fluorescence detection enabled us to study chemical reactions on the single-particle level, down to temperatures of T approximately 1 K. In the current paper, we present a detailed characterisation of the scope and limitations of this method based on our study of the reaction between laser-cooled Ca+ ions and velocity-selected CH3F molecules. The properties of our cold-neutrals source and the dependence of the measured rate constant on the shape of the Coulomb crystals, trapping and laser-cooling parameters are discussed. An extension of our technique for the study of low-temperature reactions with sympathetically cooled molecular ions (translational temperature T > 10 mK) is presented and first results on the charge-transfer reaction between OCS+ and ND3 are discussed. Finally, perspectives for further developments of our method are explored.

Faraday Discussions•Jan 1, 2009•76 citations
Ion Coulomb crystals are ordered structures of atomic or molecular ions stored in ion traps at temperatures close to the absolute zero point. These unusual “crystals” form the basis of extremely accurate clocks, provide an environment for precise studies of chemical reactions and enable advanced implementations of the technology for a quantum computer. In this article, we discuss the techniques for generating atomic and molecular Coulomb crystals and highlight some of their applications.
Ensembles of cold atomic and molecular ions in ion traps prepared at millikelvin temperatures by laser and sympathetic cooling have recently found considerable interest in both physics and chemistry. At very low temperatures the ions form ordered structures in the trap also known as "Coulomb crystals". Ion Coulomb crystals exhibit a range of intriguing properties which render them attractive systems for novel experiments in chemical dynamics, ultrahigh-resolution spectroscopy and quantum-information processing. In this article we review the methods used to prepare atomic and molecular ion Coulomb crystals and discuss some recent studies in mass spectrometry, low-temperature chemistry and precision spectroscopy to illustrate their scientific potential for chemical applications. Finally, we conclude with an outlook on outstanding challenges and prospective further developments in the field.
The generation and study of 'cold' gas-phase molecules characterised by very low translational temperatures Ttrans ? 1 K is an upcoming field of research in physical chemistry which has received considerable attention over the past years. A particular interesting form of cold molecules are ensembles of cold localised cations in ion traps which form ordered structures known as 'Coulomb crystals'. The present article reviews the experimental methods used for the generation of atomic and molecular Coulomb crystals and highlights recent experiments which take advantage of their intriguing properties in order to study chemical reactions at very low temperatures with single-particle sensitivity.
Ion Coulomb crystals, formed by atomic ions at low temperatures in radiofrequency and Penning ion traps, are structures that have remarkable properties and many applications. Images of Coulomb crystals are striking and reveal the crystal structure, which arises from a balance between the trapping forces acting on the ions and their mutual Coulomb repulsion. Applications of these structures range from frequency standards and quantum simulation through to measurement of the cross-sections of chemical reactions of ions.
Laser cooling of atomic ions has long been used as a tool in physics to explore quantum entanglement for applications in quantum computing and information. More recently, laser-cooled atomic ions have been used as a platform for studying cold chemistry. Here, we describe an experimental system called a “Coulomb crystal,” where laser-cooled ions are confined in traps at sufficiently low translational energies that they form an ordered structure. We then present a range of experiments undertaken using this platform, from studies of reactions with an atomic species to reaction systems of increased complexity, involving molecular ions and neutral molecules. We also describe a few spectroscopic studies enabled by Coulomb crystals before discussing some possible future directions of the field. This is not meant to be a comprehensive review of the entire field, but rather a sampling of the types of experiments that can be performed and the knowledge gained from these studies.
In this Perspective, we examine the use of laser-cooled atomic ions and sympathetically cooled molecular ions in Coulomb crystals for molecular spectroscopy. Coulomb crystals are well-isolated environments that provide localization and long storage times for sensitive measurements of weak signals and cold temperatures for precise spectroscopy. Coulomb crystals of molecular and atomic ions enable the detection of single-photon molecular ion transitions at a range of wavelengths by a change in atomic ion fluorescence at visible wavelengths. We give an overview of the state of the art from action spectroscopy to quantum logic spectroscopy for a wide range of molecular transitions from rotational sublevels separated by 10 –7 cm –1 to rovibronic transitions at 25 000 cm –1 . We emphasize how this system allows for unparalleled control of the molecular ion state for precision spectroscopy with applications in astrochemistry and fundamental physics. We conclude with an outlook of the use of this control in cold molecular ion reactions.
The recent development of a range of techniques for producing cold atoms and molecules at very low translational temperatures T < or = 1 K has provided the opportunity to investigate collisional processes in a new physical regime. We have recently presented a new experimental method to study low-temperature reactive collisions between translationally cold ions and neutral molecules (S. Willitsch et al., Phys. Rev. Lett. 2008, 100, 043203). Our technique relies on the combination of a quadrupole-guide velocity selector for the generation of translationally cold neutral molecules with a facility to produce ordered structures of cold ions (Coulomb crystals) by laser cooling in a linear quadrupole ion trap. The strong localisation of the ions in the trap in combination with the high sensitivity of laser-induced-fluorescence detection enabled us to study chemical reactions on the single-particle level, down to temperatures of T approximately 1 K. In the current paper, we present a detailed characterisation of the scope and limitations of this method based on our study of the reaction between laser-cooled Ca+ ions and velocity-selected CH3F molecules. The properties of our cold-neutrals source and the dependence of the measured rate constant on the shape of the Coulomb crystals, trapping and laser-cooling parameters are discussed. An extension of our technique for the study of low-temperature reactions with sympathetically cooled molecular ions (translational temperature T > 10 mK) is presented and first results on the charge-transfer reaction between OCS+ and ND3 are discussed. Finally, perspectives for further developments of our method are explored.