Michael Storch

Molekülgeometrie und angeregte Elektronenzustände, XXII: Quantenchemische Untersuchungen zur Molekülgeometrie und zum vibronischen Spektralverhalten von ausgewählten Borchelaten

SummaryThe theoretical completely-optimized molecular geometries of selected boron chelates calculated by means of the semi-empirical Warshel-Karplus method, are presented for the electronic states S0, S1 and T1. On this basis the vibronic spectral behaviour in absorption, fluorescence and phosphorescence has been determined by computing the Franck-Condon weighted density functions within the framework of the Condon approximation. The theoretical results obtained are compared with the experimental S1 ← S0 absorption, S1 → S0 fluorescence and T1 → S0 phosphorescence, and interpreted with respect to the active vibrational modes. The calculated geometry changes are found to be largely attributed to those modes responsible for the fine structure of the corresponding spectroscopic transitions.

Vibronisches Spektralverhalten von Molekülen: Theoretische Analyse der Phosphoreszenz von Naphthalen und seiner perdeuterierten Verbindung

On the basis of completely-optimized S0 and T1 molecular geometries the phosphorescence of naphthalene and of its perdeuterated compound has been calculated. The results obtained are compared with the experimental vibrationally-structured spectra.

Nicht-radiative Desaktivierung von Molekülen: III. Theoretische Bestimmung der inneren Konversion von ausgewählten 1,3-Diketonato-Borkomplexen unter Berücksichtigung des Akzeptor- und Promotorverhaltens

SummaryTaking as a basis the completely-optimized S0 and S1 molecular geometries of selected 1,3-diketonato boron complexes the rate constants of internal conversion and fluorescence are determined theoretically. It is shown that the consideration of the accepting as well as promoting modes is essential to get a more substantiated insight into the photophysics of these compounds. An analysis of the significant modes is given.

Vibronisches Spektralverhalten von Molekülen: XX. Theoretische Untersuchung der S2←S0-Absorption des Pyrens im Rahmen der Herzberg-Teller-Näherung erster Ordnung

SummaryOn the basis of the completely-optimized S0 and S2 molecular geometries of pyrene the vibrational structure of the electronic S2←S0 transition was calculated within both the Condon approach and the first-order Herzberg-Teller approach. The theoretical results demonstrate the significant influence of vibronic coupling. An analysis of the active vibrational modes is given. The theory-experiment comparison within the Herzberg-Teller approach is satisfactory.

Vibronisches Spektralverhalten von Molekülen, 16. Mitt.: Theoretische Molekülgeometrien und Spektrumstruktur der Fluoreszenz des Anthanthrens

SummaryCompletely-optimized S0 and S1 molecular geometries of anthanthrene and the theoretical vibronic line spectrum of the S1 → S0 fluorescence are presented. The experimental spectroscopic peaks are satisfactorily reproduced by the calculated vibronic transitions within the Condon approach. An analysis of the active vibrational modes being responsible for the spectrum structure is given. The photophysical S1 state deactivation of anthanthrene is discussed with respect to the fluorescence and internal conversion quantum yields.

Vibronisches Spektralverhalten von Molekülen: XIV. Zum Einfluß der vibronischen Kopplung auf die S0-S1-Absorption und Fluoreszenz von ausgewählten 1,3-Diketonato-bor-komplexen im Rahmen der Herzberg-Teller-Näherung

SummaryBased upon completely-optimized S0 and S1 molecular geometries the vibrational structures of S0-S1 absorption and fluorescence transitions of selected 1,3-diketonato boron complexes being differently substituted, are calculated within the Herzberg-Teller approach taking into account vibronic coupling contributions. In dependence on substituted diketone as well as on the co-ligand, the influence of vibronic coupling and the consequences of intensity borrowing on the spectral behaviour in absorption and fluorescence are found to be quite different for the studied boron complexes. Consequently, for some complexes their spectroscopic properties may be interpreted exclusively by means of the Herzberg-Teller approach. An analysis of the relevant vibrational modes is given.

Vibronisches Spektralverhalten von Molekülen, 19. Mitt. S1→S0-Fluoreszenz des Phenanthrens im Rahmen der Herzberg-Teller-Näherung erster Ordnung

SummaryOn the basis of the completely-optimized S0 and S1 molecular geometries of phenanthrene the vibrational structure of the S1 → S0 transition was calculated within the first order Herzberg-Teller approach including also the Dushinsky transformation of normal mode vectors. The influence of the vibronic coupling and of the Dushinsky effect on the spectral behaviour is discussed with respect to intensity redistributions. The experimental fluorescence is sufficiently reproduced by the theoretical vibronic S1 → S0 “line” spectrum as the Dushinsky effect is taken into account. An analysis of the relevant vibrational modes is given.

The vibronic spectral behaviour of molecules: A theoretical study of the T1→S0 phosphorescence of isomeric phenyl naphthalenes☆

Abstract Theoretical vibronic T 1 →S 0 “line” spectra of the isomeric phenylnaphthalenes, calculated within the Condon approach on the basis of completely optimized S 0 and T 1 molecular geometries, are presented and compared with experimental phosphorescence spectra. The theory-experiment comparison is satisfactory after taking into account the Dushinsky transformation. An analysis of the vibrational modes responsible for the spectral structure is given.