Friday, November 30, 2012

Electronic Spectra of Protonated Benzaldehyde Clusters with Ar and N2: Effect of ππ* Excitation on the Intermolecular Potential


Electronic spectra of the S1←S0 transition of dimers of protonated benzaldehyde (BZH+) with Ar and N2 are recorded by resonance-enhanced photodissociation in a tandem mass spectrometer. The S1 origins observed are shifted to higher frequency upon complexation with Ar (ΔS1 = 300 cm−1) and N2 (ΔS1 = 628 cm−1). Ab initio calculations at the CC2/aug-cc-pVDZ level suggest an assignment to H-bonded dimers of L = Ar and N2 binding to the cis isomer of O-protonated BZH+, yielding values of ΔS1 = 242 and 588 cm−1 for cis-BZH+-L(H). Electronic ππ* excitation results in a substantial increase of the proton affinity of BZH+, which in turn destabilizes the intermolecular H-bonds to the inert ligands by 35%. The drastic effects of electronic ππ* excitation on the geometric and electronic structure as well as the strength and anisotropy of the intermolecular potential (H-bonding and π-bonding) are investigated.



Electronic Spectra of Protonated Benzaldehyde Clusters with Ar and N2: Effect of ππ* Excitation on the Intermolecular Potential. Alexander Patzer, Max Zimmermann, Ivan Alata, Christophe Jouvet, and Otto Dopfer. The Journal of Physical Chemistry A 2010 114 (48), 12600-12604

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The "Silver Song"

Este video es obra creativa de Armando Isaac, para el curso de Química Inorgánica I.