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RESEARCH PRODUCT
Excited states of the water molecule: Analysis of the valence and Rydberg character
Luis Serrano-andrésMercedes RubioManuela Merchánsubject
General Physics and AstronomyElectronssymbols.namesakeAb initio quantum chemistry methodsMoleculePhysics::Atomic PhysicsSinglet statePhysical and Theoretical Chemistry:FÍSICA::Química física [UNESCO]Valence (chemistry)ChemistryAb initio calculations ; Molecular configurations ; Orbital calculations ; Quantum chemistry ; Rydberg states ; SCF calculations ; Valency ; WaterValencyWaterRydberg statesMolecular configurationsUNESCO::FÍSICA::Química físicaOrbital calculationsExcited stateRydberg atomRydberg formulasymbolsQuantum TheorySCF calculationsAb initio calculationsIonization energyAtomic physicsQuantum chemistryAlgorithmsdescription
The excited states of the water molecule have been analyzed by using the extended quantum-chemical multistate CASPT2 method, namely, MS-CASPT2, in conjunction with large one-electron basis sets of atomic natural orbital type. The study includes 13 singlet and triplet excited states, both valence and 3s-, 3p-, and 3d-members of the Rydberg series converging to the lowest ionization potential and the 3s- and 3p-Rydberg members converging to the second low-lying state of the cation, 1 math. The research has been focused on the analysis of the valence or Rydberg character of the low-lying states. The computation of the 1 math state of water at different geometries indicates that it has a predominant 3s-Rydberg character at the equilibrium geometry of the molecule but it becomes progressively a valence state described mainly by the one-electron 1b1→4a1 promotion, as expected from a textbook of general chemistry, upon elongation of the O–H bonds. The described valence-Rydberg mixing is established to be originated by a molecular orbital (MO) Rydbergization process, as suggested earlier by R. S. Mulliken [Acc. Chem. Res. 9, 7 (1976)] . The same phenomenon occurs also for the 1 math state whereas a more complex behavior has been determined for the 2 math state, where both MO Rydbergization and configurational mixing take place. Similar conclusions have been obtained for the triplet states of the molecule. Mercedes.Rubio@uv.es Luis.Serrano@uv.es Manuela.Merchan@uv.es
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2008-01-01 | The Journal of Chemical Physics |