Publications related to Internal conversion (chemistry)

Single molecule fluorescence and phosphorescence studies using a scanning tunneling microscope

This thesis investigates novel single-molecule luminescence phenomena at their inherent, sub-molecular length scale. The microscopic understanding of luminescence processes will be crucial for the continued improvement of organic optoelectronic and semicon ...

EPFL2022

Ultrafast Photoelectron and Optical Spectroscopies of Photoinduced Processes in Molecular Systems in Solution

Luca Longetti

Investigating molecular excitations with femtosecond time resolution is of pivotal importance to understand the out-of-equilibrium processes taking place in molecular systems upon light absorption. The photochemistry of solvated species is heavily determin ...

EPFL2020

The stereodynamics of ion forming reactions

Andreas Osterwalder, Sean Dennis Steven Gordon

Energy transfer reactions occur in all areas of chemistry. One fundamental form of this is demonstrated by reactions in which an electronically excited atom transfers energy to a neutral, resulting in spontaneous ionisation, potentially combined with compl ...

2020

Non-equilibrium dynamics of di-platinum complexes and molecular dyes in solution: Insights from transient absorption and two-dimensional Fourier transform spectroscopy

Lars-Hendrik Mewes

Unraveling the interplay between electronic- and vibrational degrees of freedom on the earliest time scales of physical, chemical and biological processes is crucial to gaining insight into the mechanisms that govern the world around us, since it is during ...

EPFL2019

Effects of Ozone on the Photochemical and Photophysical Properties of Dissolved Organic Matter

Urs von Gunten, Frank Jonathan Leresche, Silvio Canonica

This study focused on the effects of ozonation on the photochemical and photophysical properties of dissolved organic matter (DOM). Upon ozonation, a decrease in DOM absorbance was observed in parallel with an increase in singlet oxygen (O-1(2)) and fluore ...

AMER CHEMICAL SOC2019

Mechanism of ultrafast non-reactive deactivation of the retinal chromophore in non-polar solvents

Goran Zgrablic

The photoisomerization of the all-trans protonated Schiff base of retinal (SBR+) in solution is highly inefficient. The present theoretical and experimental investigation aims at disclosing the mechanisms of ultrafast, non-reactive relaxation of SBR+ that ...

Royal Soc Chemistry2017

Ultrafast Photophysics of Transition Metal Complexes

Majed Chergui

CONSPECTUS: The properties of transition metal complexes are interesting not only for their potential applications in solar energy conversion, OLEDs, molecular electronics, biology, photochemistry, etc. but also for their fascinating photophysical properti ...

American Chemical Society2015

Fragmentation mechanism of UV-excited peptides in the gas phase

Thomas Rizzo, Oleg Boyarkine, Michael Zachary Kamrath, Aleksandra Zabuga

We present evidence that following near-UV excitation, protonated tyrosine- or phenylalanine–containing peptides undergo intersystem crossing to produce a triplet species. This pathway competes with direct dissociation from the excited electronic state and ...

American Institute of Physics2014

Dynamics of UV-excited, protonated peptides in the gas phase

Aleksandra Zabuga

The scope of this thesis is the electronically excited state dynamics of protonated peptides and their photofragmentation mechanism. UV radiation induces fragmentation of biological molecules and might cause various diseases, such as cataracts or skin canc ...

EPFL2014

Polychromatic femtosecond fluorescence studies of metal-polypyridine complexes in solution

Majed Chergui, Andrea Cannizzo, Olivier Christian Bräm, Ahmed Maher Fahmy El-Zohry

Femtosecond-resolved broadband fluorescence studies are reported for M(bpy)(3) (M = Fe, Ru), RuN3 and RuN719 complexes in solution. We investigated the pump wavelength dependence of the fluorescence of aqueous Fe(bpy)(3) and the solvent and li ...

2012

Ln(III)-cored complexes based on boron dipyrromethene (Bodipy) ligands for NIR emission

Jean-Claude Bünzli

Two Bodipy-based chromophores have been synthesized, which bear two methoxyphenyl substituents in the 1,7 positions and either hydrogen (L1) or bromine (L2) atoms in the 2,6 positions, with the aim of testing their ability to sensitize the luminescence of ...

2012

Binding of Biotin to Streptavidin: A combined fluorescence correlation spectroscopy and time-resolved fluorescence study

Mostafa Shalaby

The Biotin-Streptavidin complex is a widely studied system in biology and biophysics, because of its extremely strong non-covalent binding affinity. The latter is often exploited to link molecules to substrates or to one another. However, the details of th ...

2011

Time-Resolved Optical and X-Ray Spectroscopy of Rhenium Based Molecular Complexes

Amal El Nahhas

The photocycle of rhenium carbonyl complexes, type facial-[Re(L)(CO)3(diimine)]n [L=halide / n=0, L=4-Ethyl-pyridine (Etpy)- Imidazole (ImH) /n=+1, diimine= bpy , 10- phenanthroline (phen), 4,4'-dimethyl-2,2'-bpy (dmb)] was studied using a set of ultrafast ...

EPFL2010

Femtosecond Fluorescence and Intersystem Crossing in Rhenium(I) Carbonyl-Bipyridine Complexes

Majed Chergui, Andrea Cannizzo, Amal El Nahhas

Ultrafast electronic-vibrational relaxation upon excitation of the singlet charge-transfer b1A' state of [Re(L)(CO)3(bpy)]n (L = Cl, Br, I, n = 0; L = 4-Et-pyridine, n = 1+) in acetonitrile was investigated using the femtosecond fluorescence up-conversion ...

2008

Hot Adsorbate-Induced Retardation of the Internal Thermalization of Nonequilibrium Electrons in Adsorbate-Covered Metal Nanoparticles

Hubert Girault, Christophe Bauer, Jean-Pierre Abid

Femtosecond transient absorption spectroscopy has been used to investigate the electron-electron scattering dynamics in sulfate-covered gold nanoparticles of 2.5 and 9.2 nm in diameter. We observe an unexpected retardation of the absolute internal thermali ...

2006