Electron transmission spectroscopy hydrocarbons

Photoelectron spectroscopy (PES) Q, and more recently electron transmission spectroscopy (ETS) (3, 4) have provided much information on the cation and anion states, respectively, of many hydrocarbons. Within the context of the Koopmans Theorem (KT) approximation, the cation states can often be associated with the filled orbitals and the anion states with the unfilled orbitals of a molecule. In this sense these two methods are complementary. However there are important distinctions between these two spectroscopic methods which arise in part from the very different lifetimes of the anions and cations. 

In these examples, the metastable H2 does not actually undergo electron loss because the Na or Mg Ion "retrieves the electron as the complex dissociates leaving the H2 vlbratlonally excited and the Na or Mg atom In Its ground state. Recent work on electron transmission spectroscopy studies of unsaturated hydrocarbons (24) demonstrates that electronic shape resonances may be essentially ubiquitous In chemical systems which possess low-energy vacant orbitals and the availability of electron density to enter such orbitals. 

This paper summarizes the first investigations of three- and four-membered ring compounds by the technique of electron transmission spectroscopy (ETS). He will briefly discuss two general areas associated with the negative ion states of small ring hydrocarbons ... 

Covering monometallic (Pd, Sn) and multimetallic (Pd-Sn, Pd-Ag) systems, several examples are presented in this chapter to illustrate the possibility offered by this chemistry to control the particle size distribution and the bimetallic interaction at a molecular level. This work is supported by a multitechnique characterization approachusing SnM6ssbauerspectroscopy,X-rayphotoelectron spectroscopy (XPS), low-energy ion spectroscopy (LEIS), and transmission electron microscopy (TEM). Catalytic performances in hydrogenation of different unsaturated hydrocarbons (phenylacetylene, butadiene) are finally discussed in order to establish structure-reactivity relationships. 

TCLP TDB TDF THC TBP TEM TLM TM-AFM TOC TRLFS TRU TSP TST TVS Toxicity characteristics leaching procedure Thermodynamic database Tyre-derived fuel Total hydrocarbon Tri-n-butyl phosphate Transmission electron microscopy Triple layer model Tapping mode atomic force microscopy Total organic carbon Time-resolved laser fluorescence spectroscopy Transuranic Total suspended particles Transition state theory Transportable vitrification system... 

Schematic models for the expanded structure of bile acid-phosphatidylcholine mixed micelles are shown in Fig. 2B. The original model was proposed by Small in 1967 (S36). In this model the mixed micelle consisted of a phospholipid bilayer disk surrounded on its perimeter by bile acid molecules, which were oriented with their hydrophilic surhices in contact with aqueous solvent and their hydrophobic sur ces interacting with the hydrocarbon chains of the phosphohpid molecules. This model has recently been revised, based on further studies of mixed micelles using quasi-elastic light scattering spectroscopy (M20). In a new model for the molecular structure of bile acid-phospholipid mixed micelles. Mazer et al. (M20) propose a mixed disk, in which bile acids are found not only on the perimeter of phospholipid bilayers, but also incorporated within their interior in high concentrations (Fig. 2B). The size of these mixed micelles was estimated to be as high as 200 to 400 A in radius in some solutions, and disk-shaped particles in this size range were observed by transmission electron microscopy (M20). Micellar aggregates similar in size and structure to those found in model bile solutions have been demonstrated in dog bile (M22).

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