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Published on: April 17, 2026
Franck-Condon simulations of clusters: phenol-nitrogen
Igor Pugliesi1, M J Watkins, Klaus Müller-Dethlefs
1Department of Chemistry, York Centre of Laser Spectroscopy, YCLS, The University of York, Heslington, York YO10 5DD, UK. igor.pugliesi@gmail.com
The Journal of Physical Chemistry. A
|April 8, 2006
Summary
Multidimensional Franck-Condon simulations accurately predict phenol-nitrogen mass-analyzed threshold ionization (MATI) spectra, but underestimate resonance enhanced multiphoton ionization (REMPI) spectra. SACCI optimized geometries yield the best simulation results.
Area of Science:
- Physical Chemistry
- Computational Quantum Chemistry
- Spectroscopy
Background:
- Resonance enhanced multiphoton ionization (REMPI) and mass-analyzed threshold ionization (MATI) are powerful spectroscopic techniques.
- Accurate theoretical simulations are crucial for interpreting complex molecular spectra, especially for van der Waals clusters like phenol-nitrogen.
- Previous studies have explored various computational methods for simulating ionization spectra, with varying degrees of success.
Purpose of the Study:
- To perform multidimensional Franck-Condon simulations for phenol-nitrogen using different computational geometries.
- To evaluate the accuracy of these simulations for both REMPI and MATI spectra.
- To identify the optimal computational method and geometries for simulating the ionization spectra of phenol-nitrogen.
Main Methods:
- Multidimensional Franck-Condon simulations were employed.
- Geometries were optimized using complete active space self-consistent field (CASSCF), multi-reference configuration interaction (MRCI), and symmetry-adapted cluster configuration interaction (SACCI) methods.
- Simulations were compared against experimental REMPI and MATI spectra of phenol-nitrogen.
Main Results:
- REMPI simulations showed significant underestimation of intermolecular mode transitions and their intensities compared to intramolecular modes.
- MATI spectra simulations demonstrated good agreement with experimental data.
- Symmetry-adapted cluster configuration interaction (SACCI) optimized geometries provided the most accurate simulations for both REMPI and MATI spectra.
Conclusions:
- Multidimensional Franck-Condon simulations are more successful in reproducing MATI spectra than REMPI spectra for phenol-nitrogen.
- SACCI optimized geometries are recommended for accurate simulation of ionization spectra in such systems.
- The prominent Franck-Condon envelopes in MATI spectra are attributed to sigma and sigma + ngamma' combination bands.
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