Characterization of gas phase iron phthalocyanine with X-ray photoelectron and absorption spectroscopies

Despite the numerous studies dedicated to phthalocyanine molecules adsorbed on surfaces, in monolayer or thin film, very few works have been focused on the characterization of vapors of these molecules. In this article we present the C 1s, N 1s and Fe 2p photoemission results as well as N K-edge X-ray absorption data of iron phthalocyanine (FePc) in gas phase. Presented comparison of X-ray photoelectron spectroscopy and X-ray absorption spectroscopy spectra of FePc films show a great similarity with the gas phase results, con- firming the molecular character of thick films. The Fe 2p photoemission spectrum of the gas phase FePc, shown for the first time, can be considered as a fingerprint of the Fe(II) ionic state of the central metal of the iron phthalocyanine. The performed multiplet calculations for describing the Fe 2p XP spectrum indicate 3 Eg (a1g 2 eg 3 b2g 1 ) state as the most probable ground state for thick film of iron phthalocyanine

The Low Density Matter (LDM) beamline at FERMI: Optical layout and first commissioning

The Low Density Matter (LDM) beamline has been built as part of the FERMI free-electron laser (FEL) facility to serve the atomic, molecular and cluster physics community. After the commissioning phase, it received the first external users at the end of 2012. The design and characterization of the LDM photon transport system is described, detailing the optical components of the beamline

The Role of the Partner Atom and Resonant Excitation Energy in Interatomic Coulombic Decay in Rare Gas Dimers

We provide experimental evidence for interatomic Coulombic decay (ICD) in mixed rare gas dimers following resonant Auger decay. A velocity map imaging apparatus together with a cooled supersonic beam containing Ar2 and NeAr dimers was used to record the energy and angular distributions of electrons in coincidence with two mass selected ions following the excitation of a number of resonances converging to the Ar 2p3/2\u20131 threshold using synchrotron radiation. It is shown that the ICD process can be controlled by the choice of the partner atom in the dimer or of the resonance that triggers the resonant Auger deca

Vibrationally resolved high-resolution NEXAFS and XPS spectra of phenanthrene and coronene

We performed a combined experimental and theoretical study of the C1s Near-Edge X-ray Absorption Fine-Structure (NEXAFS) spectroscopy and X-ray Photoelectron Spectroscopy in the gas phase of two polycyclic aromatic hydrocarbons (phenanthrene and coronene), typically formed in combustion reactions. In the NEXAFS of both molecules, a double-peak structure appears in the C1s\u2192 LUMO region, which differ by less than 1 eV in transition energies. The vibronic coupling is found to play an important role in such systems. It leads to weakening of the lower-energy peak and strengthening of the higher-energy one because the 0 12 n (n > 0) vibrational progressions of the lower-energy peak appear in nearly the same region of the higher-energy peak. Vibrationally resolved theoretical spectra computed within the Frank-Condon (FC) approximation and linear coupling model agree well with the high-resolution experimental results. We find that FC-active normal modes all correspond to in-plane vibrations. \ua

A modular end-station for atomic, molecular, and cluster science at the low density matter beamline of FERMI@Elettra

The low density matter end-station at the new seeded free electron laser FERMI@Elettra is a versatile instrument for the study of atoms, molecules and clusters by means of electron and ion spectroscopies. Beams of atoms, molecules and helium droplets as well as clusters of atoms, molecules and metals can be produced by three different pulsed valves. The atomic and molecular beams may be seeded, and the clusters and droplets may be pure, or doped with other atoms and molecules. The electrons and ions produced by the ionization and fragmentation of the samples by the intense light of FERMI can be analysed by the available spectrometers, to give mass spectra and energy as well as angular distributions of charged particles. The design of the detector allows simultaneous detection of electrons and ions using velocity map imaging and time-of-flight techniques respectively. The instruments have a high energy / mass resolution and large solid-angle collection efficiency. We describe the current status of the apparatus and illustrate the potential for future experiments