The very low ionization potentials of porphyrins and the possible role of rydberg states in photosynthesis

Dupuis, P.; Roberge, R.; Sándorfy, C.

doi:10.1016/0009-2614(80)80549-5

Cited by 78 publications

(57 citation statements)

References 18 publications

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Section: Ionization Potentialssupporting

confidence: 79%

“…For comparison, ionization potentials for similar systems are reported at 6.25 to 6.80 eV (47) in very good agreement with the calculated values. For some systems a shoulder is reported about 0.13 eV higher in energy, which may correspond to the second ionization process (47). It is interesting to further note that the ionization potentials calculated for our model Co(III)Pt are slightly lower than those of Zn(I1)P and Mg(II)P, even though the former complex is locally positive.…”

Section: Ionization Potentialssupporting

confidence: 79%

“…It is interesting to further note that the ionization potentials calculated for our model Co(III)Pt are slightly lower than those of Zn(I1)P and Mg(II)P, even though the former complex is locally positive. Experimentally Mn(1I) trans-octaethylchlorin has an ionization potential about 0.27 eV less than that of free base octaethylchlorin (47). Non-planarity has very little effect on the calculated ionization potentials of ZnP.…”

Section: Ionization Potentialsmentioning

confidence: 91%

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A theoretical study of the electronic structure and spectra of metalloporphine cations

Edwards¹,

Zerner²

1985

Can. J. Chem.

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A theoretical study is made of the electronic spectra of Mg(lI), Zn(II), and Co(II1) porphine and their TI cations using the INDOIS-CI spectroscopic model. Thc calculated electronic spectra for the neutral compounds compare wcll with experiment. The two low-lying TI cations, one of ' A , , and one of 'A,, symmetry are both examined for each of these systems. The ' A , , cations are calculated to lie lower in energy than the 'A'. cations by only 4 kcal/mol, consistent with the findings that both ions are found depending on substituents and solvent.The visible region of the spectrum of the ' A , , species is predicted to consist of three separate bands decreasing in intensity with increasing energy, while that of the 'A'. species is calculated to consist of three allowed transitions of near equal intensity, in agreement with experimental findings. In general the Soret rcgion of the %,, ions is dominated by one transition, while at least three strong bands are calculated in the Soret region for the 'A2,, ions, again in reasonable accord with experiment. Charges, ionization energies, and spin densities are reported and discussed for all compounds.

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Section: Ionization Potentialssupporting

confidence: 79%

Section: Ionization Potentialssupporting

confidence: 79%

Section: Ionization Potentialsmentioning

confidence: 91%

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A theoretical study of the electronic structure and spectra of metalloporphine cations

Edwards¹,

Zerner²

1985

Can. J. Chem.

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“…In this context, the search for Rydberg excitations of porphyrins and their vdW complexes will be of considerable intrinsic interest. It is expected that the novel spectroscopic methods in seeded supersonic jets will unveil the mystery of the Rydberg states of porphyrins, which constitute an important research area pioneered by Sandorfy and co-workers (16).…”

Section: Discussionmentioning

confidence: 99%

Electronic excitations of the free-base porphine–Ar van der Waals complex

Even¹,

Jortner²,

Berkovitch‐Yellin³

1985

Can. J. Chem.

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This paper is dedicated to Professor Carnille S a r~d o ron the occasion of his 65th birthday Uzr EVEN, JOSHUA JORTNER, and ZIVA BERKOVITCH-YELLIN. Can. J. Chem. 63, 2073Chem. 63, (1985.In this paper we report on the excited-state energetics of the two lowest-lying intravalence electronic excitations So -+ S," and So -+ S l y of a large van der Waals complex, consisting of Ar bound to free-base porphine (HIP). HIP. Ar,, complexes were synthesized and interrogated by laser-induced fluorescence in seeded supersonic expansions of Ar and He/Ar. Diagnostic methods, which were based on the dependence of the intensity of the spectral features on the stagnation pressure and on spectroscopy in He(99%)/Ar(l%) mixtures, were utilized for the identification of the vibrationless electronic excitations of H,P.Ar,. The spectroscopic data were supplemented by model calculations of the potential surface, which demonstrate that the single equilibrium configuration of H2P.RI (R = Ne, Ar, Kr, and Xe) corresponds to the R atom being located at the twofold symmetry axis perpendicular to the porphyrin ring. While the intense S,, -+ S l y transition of HzP. Ar, exhibits a red, dispersive, microscopic solvent shift (6v = -24 cm-I), the So -+ SI" transition is characterized by a blue microscopic spectral shift (6v = + 8 cm-I), which provides a unique example for excited-state destabilization, originating from intramolecular configurational changes induced by van der Waals binding in a large complex. .Ar1, on a utilisC des mCthodes d'kvaluation qui sont basCes sur la relation qui existe entre I'intensitC des caractCristiques spectrales et la pression de stagnation ainsi que sur la spectroscopie dans des mClanges 2 99% He/]% Ar. On a utilisC les donnCes spectrales de concert avec des calculs modkles de la surface de potentiel qui dimontrent que la seule configuration dlCquilibre du H2P.RI (R = Ne, Ar, Kr et Xe) correspond a celle dans laquelle l'atome R se trouve au niveau de I'axe de symCtrie binaire qui est perpendiculaire au noyau de la porphyrine. Alors que la transition intense So + Sly du H,P.Ar, prCsente un dCplacement microscopique dC au solvant qui soit dispersif et qui se dCplace vers le rouge (6v = -24 cm-I), la transition So -+ S," est caractCrisCe par un dCplacement spectral microscopique vers le bleu (6v = + 8 cm-I); ces rksultats correspondent a un exemple unique de d~stabilisation de 1'Ctat excitC provenant de changements configurationnels intramolCculaires qui sont induits par un couplage de van der Waals dans un vaste complexe.[Traduit par le journal]

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“…The vertical IP computed by CASPT2 (6.84 eV) is in good agreement with the experimental value (6.9 eV). 57 The difference between the vertical and adiabatic IPs computed at 0.18 eV is an order of magnitude larger than that computed using PBE. Furthermore, we computed the IPs with CASPT2 using the PBE-optimized geometries.…”

mentioning

confidence: 85%

Communication: Automatic code generation enables nuclear gradient computations for fully internally contracted multireference theory

MacLeod

Shiozaki

2015

The Journal of Chemical Physics

111

166

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Analytical nuclear gradients for fully internally contracted complete active space second-order perturbation theory (CASPT2) are reported. This implementation has been realized by an automated code generator that can handle spin-free formulas for the CASPT2 energy and its derivatives with respect to variations of molecular orbitals and reference coefficients. The underlying complete active space self-consistent field and the so-called Z-vector equations are solved using density fitting. The implementation has been applied to the vertical and adiabatic ionization potentials of the porphin molecule to illustrate its capability.

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The very low ionization potentials of porphyrins and the possible role of rydberg states in photosynthesis

Cited by 78 publications

References 18 publications

A theoretical study of the electronic structure and spectra of metalloporphine cations

A theoretical study of the electronic structure and spectra of metalloporphine cations

Electronic excitations of the free-base porphine–Ar van der Waals complex

Communication: Automatic code generation enables nuclear gradient computations for fully internally contracted multireference theory

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