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RESEARCH PRODUCT
A theoretical determination of the electronic spectrum of formaldehyde
Björn O. RoosManuela Merchánsubject
Valence (chemistry)ChemistryEnergy minimizationsymbols.namesakeExcited stateIonizationRydberg formulasymbolsChiropracticsSinglet statePhysical and Theoretical ChemistryAtomic physicsAdiabatic processExcitationdescription
The electronically excited states of formaldehyde are examined by means of multiconfigurational second-order perturbation (CASPT2) theory with extended ANO-type basis sets. The calculations comprised five valence excited states plus all singlet 3s, 3p, and 3d members of the Rydberg series converging on the first ionization. The computed vertical excitation energies were found to be within 0.2 eV of the available experimental energies. Full geometry optimization has been performed for five valence excited states. Assuming a planar geometry, the “0-0” transition for the valence1A1(π → π*) state is calculated to appear near 7.9 eV, close to the (n y → 3p) region. This state is, however, not planar and the true adiabatic energy is 7.4 eV, which is 2.3 eV below the corresponding vertical transition.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1995-10-01 | Theoretica Chimica Acta |