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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Role of excited core Rydberg states in dissociative recombination
1Institute for Scientific Research, 22 Bonad Road, Winchester, Massachusetts 01890, USA. slg@sci.org
The Journal of Physical Chemistry. A
|June 6, 2007
Summary
Excited core states significantly influence dissociative recombination rates in molecular ions. For nitrogen (N2+), these states increase recombination coefficients by approximately fourfold, highlighting their importance.
Area of Science:
- Chemical Physics
- Atomic and Molecular Physics
- Quantum Chemistry
Background:
- Dissociative recombination (DR) of molecular ions with electrons is crucial in various plasma environments.
- Intermediate resonant states, specifically Rydberg states, significantly impact the total rate coefficient of DR.
- These resonances can be categorized into two types: those with ground-state ion cores and those with excited-state ion cores.
Purpose of the Study:
- To theoretically investigate the role of excited core states in the dissociative recombination of nitrogen ions (N2+).
- To compare the contributions of ground-core and excited-core resonances to the DR process.
- To quantify the impact of excited-core resonances on the rate coefficient for the 2(1)Sigma(g)+ dissociative pathway.
Main Methods:
- Ab initio theoretical calculations were performed.
- Potential energy curves were computed for relevant electronic states.
- Electronic widths, cross sections, and rate coefficients were calculated for the dissociative recombination of N2+ along the 2(1)Sigma(g)+ state.
Main Results:
- Ground-core resonances were found to be less significant compared to excited-core resonances for N2+ DR.
- Inclusion of excited-core resonances increased the calculated rate coefficient by approximately a factor of 4 at room temperature.
- Despite this increase, the 2(1)Sigma(g)+ state did not emerge as the dominant dissociative recombination route for N2+.
Conclusions:
- Excited-core resonances play a critical, often underestimated, role in the dissociative recombination of molecular ions.
- Theoretical calculations provide valuable insights into the mechanisms and contributions of different resonance types.
- Further research is needed to fully elucidate the pathways and importance of excited-core states in various molecular ion systems.
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