Low temperature Ion - Radical Collisions
Lead Research Organisation:
University of Sussex
Department Name: Sch of Mathematical & Physical Sciences
Abstract
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Organisations
People |
ORCID iD |
| Matthias Keller (Principal Investigator) |
Publications
Blackburn L
(2020)
The effect of the electric trapping field on state-selective loading of molecules into rf ion traps
in Scientific Reports
Calmet X
(2015)
Cosmological evolution of fundamental constants: From theory to experiment
in Modern Physics Letters A
Deb N
(2015)
Coulomb crystal mass spectrometry in a digital ion trap
in Physical Review A
Foot C
(2018)
Two-frequency operation of a Paul trap to optimise confinement of two species of ions
in International Journal of Mass Spectrometry
Gardner A
(2019)
Multi-photon ionisation spectroscopy for rotational state preparation of [Formula: see text].
in Scientific reports
| Description | - We devised a new scheme to generate state-selected nitrogen ions using a novel REMPI process. - We also numerically investigated the effect of the trapping electric field on the state selectivity of the REMP process. By using trap switching and optimised laser parameters, the ions can be loaded state-selectively into an ion trap. |
| Exploitation Route | The outcomes of our investigations are important for any experiments where state-selective loading of molecular ions is required. We expect that our findings will be applied in those type if experiment. |
| Sectors | Chemicals |
| Title | Plotted Data for paper "The effect of the electric trapping field on state-selective loading of molecules into rf ion traps" |
| Description | Plotted data for paper published in Scientific Reports [28/10/20]
This Excel file contains the data plotted in Figures 2-6,8b) in the paper. The initial Summary tab in the file explains the contents. See references below for link to other datasets for this publication. AbstractTrapped molecular ions in pure rovibronic states are desirable in experiments ranging from cold chemistry to searches for physics beyond the Standard Model. Resonance-enhanced multiphoton ionisation (REMPI) can be used to prepare molecular ions in specific internal states with high fidelities. However, in the presence of electric fields, ionisation spectra exhibit frequency shifts and the ionisation thresholds are broadened. For this reason, REMPI studies are normally conducted in low and highly homogeneous electric fields, whereas the operating principle of rf ion traps requires electric fields that vary in space and time. In order to investigate the impact of this on the state-selectivity of REMPI in ion traps, we have simulated the expected broadening of the ionisation threshold under various operating conditions of a typical linear Paul trap. In many cases, the width of the ionisation threshold exceeds the separation between rotational energy levels, preventing state-selective ionisation. Careful choice of the trapping and laser parameters during loading can reduce this broadening, enabling state-selective ionisation in some instances. Where this strategy is not sufficient, the broadening can be reduced further by rapidly switching the trapping voltages off and on again during loading. This has been demonstrated experimentally for a Coulomb crystal of 40Ca + ions without descrystallising it. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://sussex.figshare.com/articles/dataset/Plotted_Data_for_paper_The_effect_of_the_electric_trapp... |
| Title | Plotted Data for paper "The effect of the electric trapping field on state-selective loading of molecules into rf ion traps" |
| Description | Plotted data for paper published in Scientific Reports [28/10/20]
This Excel file contains the data plotted in Figures 2-6,8b) in the paper. The initial Summary tab in the file explains the contents. See references below for link to other datasets for this publication. AbstractTrapped molecular ions in pure rovibronic states are desirable in experiments ranging from cold chemistry to searches for physics beyond the Standard Model. Resonance-enhanced multiphoton ionisation (REMPI) can be used to prepare molecular ions in specific internal states with high fidelities. However, in the presence of electric fields, ionisation spectra exhibit frequency shifts and the ionisation thresholds are broadened. For this reason, REMPI studies are normally conducted in low and highly homogeneous electric fields, whereas the operating principle of rf ion traps requires electric fields that vary in space and time. In order to investigate the impact of this on the state-selectivity of REMPI in ion traps, we have simulated the expected broadening of the ionisation threshold under various operating conditions of a typical linear Paul trap. In many cases, the width of the ionisation threshold exceeds the separation between rotational energy levels, preventing state-selective ionisation. Careful choice of the trapping and laser parameters during loading can reduce this broadening, enabling state-selective ionisation in some instances. Where this strategy is not sufficient, the broadening can be reduced further by rapidly switching the trapping voltages off and on again during loading. This has been demonstrated experimentally for a Coulomb crystal of 40Ca + ions without descrystallising it. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://sussex.figshare.com/articles/dataset/Plotted_Data_for_paper_The_effect_of_the_electric_trapp... |
| Title | Simulation Code for the paper "The effect of the electric trapping field on state-selective loading of molecules into rf ion traps" |
| Description | Simulation code for paper published in Scientific Reports [28/10/2020]
See reference below for other datasets for this publication. These files should enable the user to reproduce simulations in the paper. This code can also be adapted to explore the effects of varying trap, laser and molecular beam parameters on the achievable state-selectivity of ionisation inside an rf ion trap. The Matlab (.m) files contain the simulation code for calculating the ionisation-probability-weighted distribution of ionisation thresholds in an ion trap. The four files included each consider a different case: (1) Axially_applied_electric_field_molecular_beam.m This file considers the special case of only a dc voltage applied to the axial electrodes of a linear Paul trap. The molecules are ionised from a molecular beam. (2) Axially_applied_electric_field_background_gas.m This file considers the special case of only a dc voltage applied to the axial electrodes of a linear Paul trap. The molecules are ionised from a homogeneous background gas. (3) Radially_applied_electric_field.m This file considers the special case of only a rf voltage applied to the radial electrodes of a linear Paul trap. (4) Axially_and_radially_applied_fields_molecular_beam.m This file considers the general case of both a dc voltage applied to the axial electrodes and a rf voltage applied to the radial electrodes of a linear Paul trap. The molecules are ionised from a molecular beam. Abstract:Trapped molecular ions in pure rovibronic states are desirable in experiments ranging from cold chemistry to searches for physics beyond the Standard Model. Resonance-enhanced multiphoton ionisation (REMPI) can be used to prepare molecular ions in specific internal states with high fidelities. However, in the presence of electric fields, ionisation spectra exhibit frequency shifts and the ionisation thresholds are broadened. For this reason, REMPI studies are normally conducted in low and highly homogeneous electric fields, whereas the operating principle of rf ion traps requires electric fields that vary in space and time. In order to investigate the impact of this on the state-selectivity of REMPI in ion traps, we have simulated the expected broadening of the ionisation threshold under various operating conditions of a typical linear Paul trap. In many cases, the width of the ionisation threshold exceeds the separation between rotational energy levels, preventing state-selective ionisation. Careful choice of the trapping and laser parameters during loading can reduce this broadening, enabling state-selective ionisation in some instances. Where this strategy is not sufficient, the broadening can be reduced further by rapidly switching the trapping voltages off and on again during loading. This has been demonstrated experimentally for a Coulomb crystal of 40Ca + ions without descrystallising it. |
| Type Of Technology | Software |
| Year Produced | 2020 |
| Open Source License? | Yes |
| URL | https://sussex.figshare.com/articles/software/Simulation_Code_for_the_paper_The_effect_of_the_electr... |
| Title | Simulation Code for the paper "The effect of the electric trapping field on state-selective loading of molecules into rf ion traps" |
| Description | Simulation code for paper published in Scientific Reports [28/10/2020]
See reference below for other datasets for this publication. These files should enable the user to reproduce simulations in the paper. This code can also be adapted to explore the effects of varying trap, laser and molecular beam parameters on the achievable state-selectivity of ionisation inside an rf ion trap. The Matlab (.m) files contain the simulation code for calculating the ionisation-probability-weighted distribution of ionisation thresholds in an ion trap. The four files included each consider a different case: (1) Axially_applied_electric_field_molecular_beam.m This file considers the special case of only a dc voltage applied to the axial electrodes of a linear Paul trap. The molecules are ionised from a molecular beam. (2) Axially_applied_electric_field_background_gas.m This file considers the special case of only a dc voltage applied to the axial electrodes of a linear Paul trap. The molecules are ionised from a homogeneous background gas. (3) Radially_applied_electric_field.m This file considers the special case of only a rf voltage applied to the radial electrodes of a linear Paul trap. (4) Axially_and_radially_applied_fields_molecular_beam.m This file considers the general case of both a dc voltage applied to the axial electrodes and a rf voltage applied to the radial electrodes of a linear Paul trap. The molecules are ionised from a molecular beam. Abstract:Trapped molecular ions in pure rovibronic states are desirable in experiments ranging from cold chemistry to searches for physics beyond the Standard Model. Resonance-enhanced multiphoton ionisation (REMPI) can be used to prepare molecular ions in specific internal states with high fidelities. However, in the presence of electric fields, ionisation spectra exhibit frequency shifts and the ionisation thresholds are broadened. For this reason, REMPI studies are normally conducted in low and highly homogeneous electric fields, whereas the operating principle of rf ion traps requires electric fields that vary in space and time. In order to investigate the impact of this on the state-selectivity of REMPI in ion traps, we have simulated the expected broadening of the ionisation threshold under various operating conditions of a typical linear Paul trap. In many cases, the width of the ionisation threshold exceeds the separation between rotational energy levels, preventing state-selective ionisation. Careful choice of the trapping and laser parameters during loading can reduce this broadening, enabling state-selective ionisation in some instances. Where this strategy is not sufficient, the broadening can be reduced further by rapidly switching the trapping voltages off and on again during loading. This has been demonstrated experimentally for a Coulomb crystal of 40Ca + ions without descrystallising it. |
| Type Of Technology | Software |
| Year Produced | 2020 |
| Open Source License? | Yes |
| URL | https://sussex.figshare.com/articles/software/Simulation_Code_for_the_paper_The_effect_of_the_electr... |
| Description | Bad Honeff |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Research presentation of other researchers in the field. |
| Year(s) Of Engagement Activity | 2015 |
| Description | NerdNite |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | Presentation at a widerpublic about the research |
| Year(s) Of Engagement Activity | 2014 |
| Description | Outreach presentation |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | Presentation to a local school class. |
| Year(s) Of Engagement Activity | 2014 |
| Description | Sussex Universe Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Undergraduate students |
| Results and Impact | Presentation about reseach to Sussex students and the wider public. |
| Year(s) Of Engagement Activity | 2017 |
| Description | Teacher training conference presentation |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Schools |
| Results and Impact | Presentation at a teacher training conference at the University of Sussex about my research activities |
| Year(s) Of Engagement Activity | 2013 |