 Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles Therefore, it is necessary to understand the distribution between the phases According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution Henry's law constants of trace gases of potential importance in environmental chemistry have been collected and converted into a uniform format The compilation contains 17 350 values of Henry's law constants for 4632 species, collected from 689 references It is also available at http://wwwhenrys-laworg 

/pdf/compilation-of-henry-s-law-constants-version-4-0-for-water-58il9q0ogv.pdf

Compilation of Henry's law constants (version 4.0) for water as solvent

(b) Write out the equations for the time dependence of ρ11, ρ22, ρ12 and ρ21 assuming that a light field interaction V = -μ12Ee iωt + c.c. couples only levels |1> and |2>, and that the excited levels exhibit spontaneous decay. (8 marks) (c) Under steady-state conditions, find the ratio of populations in states |2> and |3>. (3 marks) (d) Find the slowly varying amplitude ̃ ρ 12 of the polarization ρ12 = ̃ ρ 12e iωt . (6 marks) (e) In the limiting case that no decay is possible from intermediate level |3>, what is the ground state population ρ11(∞)? (2 marks) 2. (15 marks total) In a 2-level atom system subjected to a strong field, dressed states are created in the form |D1(n)> = sin θ |1,n> + cos θ |2,n-1> |D2(n)> = cos θ |1,n> sin θ |2,n-1>

The Quantum Theory of Light

On-line monitoring of volatile organic compounds at pptv levels by means of proton-transfer-reaction mass spectrometry (PTR-MS) medical applications, food control and environmental research

Large polycyclic aromatic hydrocarbon (PAH) molecules carry the infrared (IR) emission features that dominate the spectra of most galactic and extragalactic sources. This review surveys the observed mid-IR characteristics of these emission features and summarizes laboratory and theoretical studies of the spectral characteristics of PAHs and the derived intrinsic properties of emitting interstellar PAHs. Dedicated experimental studies have provided critical input for detailed astronomical models that probe the origin and evolution of interstellar PAHs and their role in the universe. The physics and chemistry of PAHs are discussed, emphasizing the contribution of these species to the photoelectric heating and the ionization balance of the interstellar gas and to the formation of small hydrocarbon radicals and carbon chains. Together, these studies demonstrate that PAHs are abundant, ubiquitous, and a dominant force in the interstellar medium of galaxies.

Interstellar Polycyclic Aromatic Hydrocarbon Molecules

. Biomass burning (BB) is the second largest source of trace gases and the largest source of primary fine carbonaceous particles in the global troposphere. Many recent BB studies have provided new emission factor (EF) measurements. This is especially true for non-methane organic compounds (NMOC), which influence secondary organic aerosol (SOA) and ozone formation. New EF should improve regional to global BB emissions estimates and therefore, the input for atmospheric models. In this work we present an up-to-date, comprehensive tabulation of EF for known pyrogenic species based on measurements made in smoke that has cooled to ambient temperature, but not yet undergone significant photochemical processing. All EFs are converted to one standard form (g compound emitted per kg dry biomass burned) using the carbon mass balance method and they are categorized into 14 fuel or vegetation types. Biomass burning terminology is defined to promote consistency. We compile a large number of measurements of biomass consumption per unit area for important fire types and summarize several recent estimates of global biomass consumption by the major types of biomass burning. Post emission processes are discussed to provide a context for the emission factor concept within overall atmospheric chemistry and also highlight the potential for rapid changes relative to the scale of some models or remote sensing products. Recent work shows that individual biomass fires emit significantly more gas-phase NMOC than previously thought and that including additional NMOC can improve photochemical model performance. A detailed global estimate suggests that BB emits at least 400 Tg yr−1 of gas-phase NMOC, which is almost 3 times larger than most previous estimates. Selected recent results (e.g. measurements of HONO and the BB tracers HCN and CH3CN) are highlighted and key areas requiring future research are briefly discussed.

/pdf/emission-factors-for-open-and-domestic-biomass-burning-for-20tklb2vkv.pdf

Emission factors for open and domestic biomass burning for use in atmospheric models

Sticking coefficients of deuterium from CD 2 + are quantified on fusion relevant plasma sprayed tungsten and carbon fibre composite in the incident energy range from about 0–100 eV. The samples that were cut from ASDEX-Upgrade tiles are exposed to a beam of CD 2 + of specific incident energy, Einc, in the tandem mass spectrometer BESTOF in Innsbruck. Nuclear reaction analysis is performed ex-situ at IPP Garching for the quantification of deuterium content. The deuterium content difference measured on a spot before and after ion-beam exposure of the sample is assigned to the above mentioned species of hydrocarbon molecules sticking on the surface, allowing the calculation of the sticking probability of a specific deuterated molecular ion. The sticking coefficient, S, is found to depend on the incident energy and shows a maximum of about S ∼ 0.4 around Einc = 30 eV on CFC and about S ∼ 0.1 near Einc = 20 eV in case of PSW.

Reflection properties of small hydrocarbons impinging on tungsten and carbon surfaces

We have observed strong photodissociation (using visible laser light) of neutral van der Waals clusters (Ar, N2, O2, CO2, SO2, NH3) produced by supersonic expansion and detected by electron ionization/mass spectrometer. Several tests were performed, all of them supporting this surprising discovery. We suggest that Raman induced photodissociation (RIP) is responsible for this phenomenon. This first observation of Raman induced photodissociation provides a new technique for the study of neutral van der Waals clusters.

Fragmentation of neutral van der Waals clusters with visible laser light: a new variant of the Raman effect?

The use of non-equilibrium, low-temperature plasmas for materials processing is the key to the advancement of many rapidly developing technologies. The selective and highly anisotropic etching of materials and the controlled deposition of thin films in the fabrication of microelectronic structures is one important area of plasma-assisted material processing. Plasma polymerization and plasma-assisted surface modification are other areas of great technological importance. Plasma-based processes are used in about 35% of the steps involved in the manufacture of semiconductor chips and “the more sophisticated the chip, the larger the number of steps relying on plasma technology” [1]. The past five years have seen an increased level of activity in efforts to provide a more scientific underpinning of low-temperature plasma processing, a development stimulated by the 1991 National Research Council (NRC) report on “Plasma Processing of Materials: Scientific Opportunities and Technological Challenges” [1] and several related reports. Despite these efforts, low-temperature plasma technology (LTPT) today remains a discipline where technological advances routinely outpace the fundamental understanding of the key processes at a microscopic level. Even though process and reactor modeling and plasma diagnostics techniques made very promising advances, a serious lack of sufficient and sufficiently reliable collisional and spectroscopic data often prevents the exploitation of the full potential of modeling codes, CAD tools, and plasma diagnostics techniques. This has been noted in a recent follow-up NRC report on “Modeling, Simulation, and database Needs in Plasma Processing” [2]. The report cites three main reasons for the poorly developed status of the database, (i) the continued comparatively low level of research efforts in this area, (ii) little coordination between the activities of the few groups working in this field, particularly poor coordination between experimental efforts and theoretical calculations, and (iii) a very serious lack of communication between the community that generates the data and the community that uses the data.

The role of electron impact ionization cross sections in low-temperature plasmas

Electron attachment to gas phase nitrobenzene, all three isomers of mononitrotoluene and 2,4,6‐trinitrotoluene is studied by means of two crossed electron‐molecular beam experiments We point out the formation of long‐lived metastable parent anions and the most abundant anions produced via dissociative electron attachment (DEA) The experimental results are supported by quantum‐chemical calculations, to determine the electronic configuration of selected molecular orbitals or the electrostatic potential mapped on an isosurface of the total electron density to find preferential sites of electron attachment

Tilmann D. Märk

Papers

Reflection properties of small hydrocarbons impinging on tungsten and carbon surfaces

Fragmentation of neutral van der Waals clusters with visible laser light: a new variant of the Raman effect?

The role of electron impact ionization cross sections in low-temperature plasmas

Investigations Of Electron Attachment To Nitro‐Compounds Towards Explosives

Fission track temperature ages of sphene from the Caledonides in Sweden