AI Article Synopsis
- Researchers studied the photoionization and dissociative photoionization of acetaldehyde (CHCHO) using synchrotron radiation and advanced spectroscopy techniques in the 10.0-13.7 eV energy range.
- They identified two electronic states (XA' and AA") of CHCHO and measured their adiabatic ionization energies as well as the appearance energies for various fragment ions.
- The study also explored the dissociation mechanisms of CHCHO, including different processes like statistical dissociation and direct bond breaking, informed by calculations of dissociation limits.
Article Abstract
Photoionization and dissociative photoionization of acetaldehyde (CHCHO) in the 10.0-13.7 eV energy range are studied by using synchrotron radiation double imaging photoelectron photoion coincidence spectroscopy (iPEPICO). The XA' and AA" electronic states of CHCHO as well as the Franck-Condon gap region between these two states have been populated with several vibrational sequences and assigned in the high-resolution slow photoelectron spectrum (SPES). The adiabatic ionization energies (AIEs) of the XA' and AA" states are measured at 10.228±0.006 and 12.52±0.05 eV, respectively. The present results show that the XA' state is a stable state while the AA" state is fully dissociative to produce CHCO, CHO and CH fragment ions. The 0 K appearance energies (AE) of CHCO and CHO fragment ions are determined through the modeling of the breakdown diagram, i. e., AE(CHCO)=10.89±0.01 eV (including a reverse barrier of ~0.19 eV) and AE(CHO)=11.54±0.05 eV. In addition, the dissociation mechanisms of CHCHO including statistical dissociation, direct bond breaking and isomerization are discussed with the support of the calculated dissociation limits and transition state energies.
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| http://dx.doi.org/10.1002/cphc.202400208 | DOI Listing |
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