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The study of transitionmetal coordination complexes has played a key role in establishing quantum chemistry concepts such as that of ligand field theory. Furthermore, the study of the dynamics of their excited states is of primary importance in determining the de-excitation path of electrons to tailor the electronic properties required for important technological applications. This work focuses on femtosecond transient absorption spectroscopy of Cobalt tris(acetylacetonate) (Co(AcAc)(3)) in solution. The fast transient absorption spectroscopy has been employed to study the excited state dynamics after optical excitation. Density functional theory coupled with the polarizable continuum model has been used to characterize the geometries and the electronic states of the solvated ion. The excited states have been calculated using the time dependent density functional theory formalism. The time resolved dynamics of the ligand to metal charge transfer excitation revealed a biphasic behavior with an ultrafast rise time of 0.07 +/- 0.04 ps and a decay time of 1.5 +/- 0.3 ps, while the ligand field excitations dynamics is characterized by a rise time of 0.07 +/- 0.04 ps and a decay time of 1.8 +/- 0.3 ps. Time dependent density functional theory calculations of the spin-orbit coupling suggest that the ultrafast rise time can be related to the intersystem crossing from the originally photoexcited state. The picosecond decay is faster than that of similar cobalt coordination complexes and is mainly assigned to internal conversion within the triplet state manifold. The lack of detectable long living states (>5 ps) suggests that non-radiative decay plays an important role in the dynamics of these molecules.

A study of (R)-3-methylcyclopentanone [(R)-3-MCP] by photoelectron spectroscopy and photoelectron circular dichroism (PECD) is presented. The synchrotron radiation gas-phase photoelectron spectra of (R)-3-MCP were measured and are discussed on the basis of different theoretical methodologies. The experimental dichroism of (R)-3-MCP for selected deconvoluted valence states and for the carbonyl carbon 1s core state are reported and reproduced well by calculated dispersions generated by considering the contributions of two different conformers. The theoretical dichroic parameters are calculated by employing a multicentre basis set of B-spline functions and a Kohn-Sham Hamiltonian. Temperature-dependent PECD studies of the HOMO state and the carbonyl carbon 1s core level allowed the separation of the contributions of each conformer by photoelectron dichroism. This new approach clearly shows how the PECD methodology is sensitive to conformational and structural changes of unoriented (R)-3-MCP in the gas phase, opening up new perspectives in the characterisation of chiral molecular systems. Dichroism and conformers: Temperature-dependent photoelectron circular dichroism (PECD) studies of the HOMO state and the carbonyl carbon 1s core level of R-3-methylcyclopentanone (R-3-MCP) allowed to separate the contributions of each conformer, showing how the PECD methodology can be sensitive to the conformational and structural changes of unoriented chiral molecules. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A sizable enhancement of the circular dichroism in photoelectron spectroscopy has been measured and computed for the metal complex $\ensuremath{\Delta}$-cobalt(III) tris-acetylacetonate highest occupied molecular orbital state in the region of the Co $3p\ensuremath{\rightarrow}3d$ Fano resonance. In the resonance the dichroism reaches the maximum value of 5% and even changes its sign as compared to the direct photoionization channel. We ascribe this enhancement to electron correlation processes, namely, with the coupling between discrete excitations and the continuum, which is correctly described in the time dependent density functional theory (TDDFT) framework. These findings open new physical aspects of photoelectron circular dichroism that now can be interpreted not only via the simple direct ionization, but also through more complex electron correlation processes.

The adsorption configuration of a chiral amino alcohol, Dalaninol, on Cu(100) is studied with DFT ab-initio calculations. We address the case of the formation of a self-assembled monolayer that is experimentally found when depositing the molecule at room temperature. Preliminary calculations are performed for a cluster of four isolated molecules in gas phase, both at the MP2 and GGA-DFT level. Further results deal with the adsorption on the copper surface. STM images of two candidates structures are simulated and compared with experiments (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Valence band of S-(-) Methyl Lactate in the gas phase has been studied by synchrotron radiation photoelectron spectroscopy (PES), Circular Dichroism in the Angular Distribution of photoelectrons, and fragmentation. This chiral molecule presents two different functional groups (the hydroxyl and ester group), with three non-equivalent oxygen atoms clearly distinguishable in the photoelectron spectrum. CDAD in photoelectron spectroscopy combines the information of the molecular electronic states with the chiral properties of the molecule. The circular dichroism as a function of the kinetic energy of the photoelectrons, with a rich and complex oscillating dispersion, puts in evidence the sensitivity of the dichroic parameter to the conformational structural properties [1-4]. In Methyl Lactate there is the opportunity to point out the chemistry of the three different oxygen atoms and relate them to the chiral structure. The electronic structure and the conformational contribution in the photoemission profile have been interpreted with the aim of density functional and ab-initio theoretical calculations. Moreover we have studied the Methyl Lactate ionization and fragmentation thresholds in 8.5-35 eV photon energy range with synchrotron radiation, to complete the valence band study

Adsorption of d -alaninol on Cu(1 0 0) at room temperature has been investigated by photoelectron spectroscopy in the soft X-ray and VUV energy range and low energy electron diffraction (LEED). d -Alaninol was found by LEED to self-assemble at full coverage; core and valence photoemission spectra are presented at low and full coverage. Chemisorption occurs at room temperature. The bonding at low coverage takes place at the hydroxylic group; at full coverage there is evidence of bonding for both hydroxylic and amino groups.

The dynamical behavior of circular dichroism for valence photoionization processes in pure enantiomers of randomly oriented methyl-oxirane molecules has been studied by circularly polarized synchrotron radiation. Experimental results of the dichroism coefficient obtained for valence photoionization processes as a function of photon energy have been compared with theoretical values predicted by state-of-the-art ab initio density-functional theory. The circular dichroism measured at low electron kinetic energies was as large as 11%. Trends in the experimental dynamical behavior of the dichroism coefficients Di(É) have been observed. Agreement between experimental and theoretical results permits unambiguous identification of the enantiomer and of the individual orbitals.

We report a joint experimental and theoretical study of circular dichroism in the valence photoelectron spectra of a free chiral molecule. The circular dichroism in photoelectron spectroscopy is measured at the magic angle for various valence states of $R(+)$ and $S(\ensuremath{-})$ methyl-oxirane enantiomers in the vapor phase. The maximum dichroism measured is about $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$. Experimental and theoretical results are in agreement. The ab initio calculation employs a multicentric basis set of B-spline functions and a Kohn-Sham Hamiltonian.

FELs based on SASE are believed to be powerful tools to explore the frontiers of basic sciences, from physics to chemistry to biology. Intense R&D programs have started in the USA and Europe in order to understand the SASE physics and to prove the feasibility of these sources. The allocation of considerable resources in the Italian National Research Plan (PNR) brought about the formation of a CNR‐ENEA‐INFN‐University of Roma “Tor Vergata” study group. A conceptual design study has been developed and possible schemes for linac sources have been investigated, bringing to the SPARX proposal. We report in this paper the results of a preliminary start to end simulation concerning one option we are considering based on an S‐band normal conducting linac with high brightness photoinjector integrated in a RF compressor.

A dedicated beamline with a broad energy range of photons and with high flux and a high degree of circular polarization has been designed for the ELETTRA storage ring. The beamline exploits the circularly polarized radiation produced by an electromagnetic elliptical wiggler and cover the (5–1200) eV photon energy range using a double‐incidence spherical grating monochromator.

Unoxidized crystalline silicon, characterized by high purity, high homogeneity, sturdiness and an atomically flat surface, offers many advantages for the construction of electronic miniaturized biosensor arrays upon attachment of biomolecules (DNA, proteins or small organic compounds). This allows to study the incidence of molecular interactions through the simultaneous analysis, within a single experiment, of a number of samples containing small quantities of potential targets, in the presence of thousands of variables. A simple, accurate and robust methodology was established and is here presented, for the assembling of DNA sensors on the unoxidized, crystalline Si(100) surface, by loading controlled amounts of a monolayer DNA-probe through a two-step procedure. At first a monolayer of a spacer molecule, such as 10-undecynoic acid, was deposited, under optimized conditions, via controlled cathodic electrografting, then a synthetic DNA-probe was anchored to it, through amidation in aqueous solution. The surface coverage of several DNA-probes and the control of their efficiency in recognizing a complementary target-DNA upon hybridization were evaluated by fluorescence measurements. The whole process was also monitored in parallel by Atomic Force Microscopy (AFM).