6. Rehybridization of the Acceptor (RICT) 3908 7. Planarization of the Molecule (PICT) 3909 III. Fluorescence Spectroscopy 3909 A. Solvent Effects and the Model Compounds 3909 1. Solvent Effects on the Spectra 3909 2. Steric Effects and Model Compounds 3911 3. Bandwidths 3913 4. Isoemissive Points 3914 B. Dipole Moments 3915 C. Radiative Rates and Transition Moments 3916 1. Quantum Yields and Radiationless Deactivation Processes 3916

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

Artificial Molecular Rotors

In solution, biopolymers commonly fold into well-defined three-dimensional structures, but only recently has analogous behavior been explored in synthetic chain molecules. An aromatic hydrocarbon backbone is described that spontaneously acquires a stable helical conformation having a large cavity. The chain does not form intramolecular hydrogen bonds, and solvophobic interactions drive the folding transition, which is sensitive to chain length, solvent quality, and temperature.

https://science.sciencemag.org/content/sci/277/5333/1793.full.pdf

Solvophobically Driven Folding of Nonbiological Oligomers

Electron-transfer rates and electronic coupling factors for ferrocene groups attached to gold electrodes via oligo(phenylethynyl) “molecular wire” bridges of variable length and structure are reported. Attachment to gold was achieved via thiol groups at the end of the bridge opposite the ferrocene. Bridge structures were designed to promote strong coupling between gold and ferrocene, thereby promoting rapid electron transport over long distances. The effects of bridge length and of substituents on the phenyl rings in the bridge were addressed. Bridges containing between three and six phenylethynyl units were studied, and a “beta” value of 0.36 A-1 describing the exponential distance dependence of bridge-mediated electron-transfer rates was obtained. The effect on the rates of adding two propoxy groups onto one of the phenyl rings in the bridge was examined and found to be minimal. The standard electron-transfer rate constant of 350 s-1 obtained for the adsorbate with the longest bridge (six phenylethynyl ...

Electron Transfer at Electrodes through Conjugated “Molecular Wire” Bridges

Rates of Interfacial Electron Transfer through π-Conjugated Spacers

Internal rotation of the methyl group in the electronically excited state: o-, m-, and p-fluorotoluene

Spectres d'excitation en fluorescence, de fluorescence dispersee, et d'ionisation multiphotonique du tolane dans un jet supersonique. Determination du nombre quantique de vibration a l'etat fondamental electronique et de la barriere du mouvement de torsion. Discussion du potentiel de l'etat excite pour la torsion et des etats excites electroniques

Electronic spectra of tolane in a supersonic free jet: Large-amplitude torsional motion

The two‐color (1+1’) threshold photoelectron spectra of naphthalene in a supersonic free jet have been recorded via nine vibronic levels of the S1 electronic state up to about 1420 cm−1 above the S1 band origin. The threshold photoelectron spectra recorded via the S1 band origin and via totally symmetric ag vibronic levels show significant intensity in Δν=+1 transitions in nontotally symmetric vibrations having b1g symmetry indicating that the ionization transition gains significant intensity through a vibronic coupling mechanism between the two lowest doublet cationic states. The strongest departure from the expected Δν=0 propensity in the threshold photoelectron spectra occurs through excitation of the totally symmetric 8 mode having ag symmetry indicating that a considerable displacement occurs along the normal coordinate of this 8 mode upon ionization from the S1 state. The superior resolution of the threshold photoelectron technique over conventional photoelectron methods has allowed accurate values ...

Vibronic coupling in the ground cationic state of naphthalene: A laser threshold photoelectron [zero kinetic energy (ZEKE)‐photoelectron] spectroscopic study

Katsuhiko Okuyama

Papers

Internal rotation of the methyl group in the electronically excited state: o-, m-, and p-fluorotoluene

Electronic spectra of tolane in a supersonic free jet: Large-amplitude torsional motion

Vibronic coupling in the ground cationic state of naphthalene: A laser threshold photoelectron [zero kinetic energy (ZEKE)‐photoelectron] spectroscopic study

Rotational isomers of m-cresol and internal rotation of the methyl group in S0, S1, and the ion

Mode selectivity in intersystem crossing: glyoxal, methylglyoxal, and biacetyl