Infrared radiative transfer in planetary atmospheres—I. Effects of computational and spectroscopic economies on thermal heating/cooling rates

The availability of accurate spectroscopic data and improved knowledge of continuum absorption characteristics has required a further detailed study of i.r. radiative transfer. A sophisticated radiative transfer scheme based upon the Mayer-Goody random band model is developed and the derived transmissivities for H₂O, CO₂ and O₃ are calibrated against laboratory measurements. This calibrated scheme is used to assess the effects on calculated heating/cooling rate profiles of introducing computational and spectroscopic economies.     

A journey through quality control

The Euroanalysis VII conference in Vienna included a two-day session: Quality Assurance in Analytical Chemistry. The contributions comprised 15 lectures devoted to: intra-laboratory quality measures, inter-laboratory control, formal aspects and accreditation and implementation. The paper presents an overview of the main items developed by the contributors.A survey on the session on Quality Assurance in Analytical Chemistry of Euroanalysis VIIThe authors thank the organizers of EUROANALYSIS VII and in particular Dr. B. Griepink and Dr. E. Maier of the Community Bureau of Reference (BCR) of the CEC for their support and considerable contributions.     

Line assignments and intensities of the ν2 + ν3 − ν2 band of 12CH4

As part of a comprehensive effort to compile line parameters of methane from 2400 to 3200 cm^?1, the P and R branches of the ν₂ + ν₃ ? ν₂ band of CH₄ at 3010 cm^?1 were assigned through upper state J = 9. The process utilized the analysis of ν₂ + ν₃ at 4544 cm^?1 by J. C. Hilico, J. Degni, J. P. Champion, and G. Guelachvili (J. Mol. Spectrosc.81, 277–302 (1980)) and the ν₂ levels derived from the infrared spectrum by Margolis (in preparation) to predict the positions of the hot band. Experimentally determined lower-state energies were used to confirm assignments, and line intensities of the 300 transitions assigned are observed on the order of 10^?3 cm^?2 atm^?1 or less.     

Line intensities of Co2 in the 2.0 micron region

The line intensities of the three δ-δ bands of CO₂ and their associated Π-Π hot bands in the 2.0 υ region have been measured using a combination of long optical paths and low sample pressures with high resolution (0.035 cm^-1). These intensities yield total band strengths of 0.200, 0.969, 0.288, 0.0017, 0.062 and 0.028 cm^-2 atm^-1 at 296 K for the 04⁰1-00⁰0, 12⁰1-00⁰0, 20⁰1-00⁰, 05¹1-01¹0, 13¹1-01¹0 and 21¹1-01 ¹0 bands, respectively. The rotationless dipole moment matrix element and the German-Wallis coefficients are also determined for each band.     

Ultrafast dynamics in the dispersed phase of oil-in-water microemulsions: monosubstituted benzenes incorporated into dodecyltrimethylammonium bromide (DTAB) aqueous micelles

Time-resolved optical Kerr effect spectroscopy has been used to probe the molecular environment afforded by the hydrophobic core of oil-in-water microemulsions. This was achieved by measuring the ultrafast dynamics of a series of benzene derivatives (benzonitrile, nitrobenzene, fluorobenzene, styrene, and toluene) incorporated as the oil phase within oil-in-water microemulsions and comparing them to the dynamics in neat liquid and the liquid diluted in nonpolar solvent. Polar and strongly interacting liquids (benzonitrile and nitrobenzene) showed dynamics in the microemulsion that are similar to those in the solution phase, while weakly interacting and mildly polar liquids (fluorobenzene, styrene and toluene) reveal dynamics more similar to those of the neat liquid. This suggests stabilization of the polar dispersed phase in polar regions of the micelle.     

Delicious not siliceous: expanded carbohydrates as renewable separation media for column chromatography

Expansion of native corn starch produces a high surface area mesoporous material capable of acting as a novel stationary phase for separating various mixtures of compounds.     

Analysis of the ν1 and ν2 + ν4 bands of 12CH4

Line assignments, positions, strengths, and experimentally determined upper states are reported for the ν₁ and ν₂ + ν₄ infrared bands of ¹²CH₄. The bands have been analyzed using infrared spectra recorded with different optical densities and temperatures at 0.02- and 0.01-cm^?1 resolution using a four-passed grating spectrometer at Florida State University and a Fourier transform spectrometer at Kitt Peak National Observatory. Both ν₁ and ν₂ + ν₄ lines are assigned through J′ = 14. For J′ ≥ 10, the upper state of the vibrationally infrared inactive ν₁ band interacts strongly with ν₂ + ν₄ and is observed in the infrared spectrum with line strengths on the order of 10^?3 cm^?2 atm^?1. The upper-state energies and transition intensities are calculated from the molecular constants and transition moment matrix elements obtained through a simultaneous analysis of ν₁, ν₃, ν₂ + ν₄, 2ν₄, and 2ν₂.     

Towards a unified bifurcation theory

Bifurcation theories for the instability of slowly evolving systems have been developed in various disciplines, and a first step is here taken towards some desirable unification. A modern account of the authors' general branching theory for discrete systems is first presented, some new features being the introduction of principal imperfections and the delineation of the important semi-symmetric points of bifurcation. This theory, embedded in a perturbation approach ideal for quantitative analysis, is complementary to the far-reaching qualitative catastrophe theory of René Thom which offers a profound topological classification of instability phenomena. For this reason, we present here a detailed correlation of the two theories. Also presented in the paper is a survey of some fields of application ranging from classical fields such as hydrodynamics, through thermodynamics, crystallography and cosmology, to the newer domains of biology and psychology.