Helium and self-broadening in the first and second overtone bands of 12C16O

The pressure broadening coefficients for rotation-vibration lines of J states up to 22 in the 2-0 band and J states up to 20 in the 3-0 band of pure CO and HeCO mixtures were measured. The data were obtained at room temperature utilizing a Fourier transform spectrometer and various cells, including a 113-m White cell. These data exhibit little change with increasing vibrational level, and in the case of helium broadening, only slight J dependence.     

The spectral theory for a pencil of skewsymmetrical differential operators of the third order

We consider the linear algebra of a pair of skewsymmetrical forms in the space of periodic functions defined by differential operators. By linear transform in the space of functions we reduce this pair to the simplest possible form. In this process, we prove the theorem of reduction in rather general context. © 1994 John Wiley & Sons, Inc.     

Orthogonalization of Polyaryl Linkers as a Route to More Porous Phosphonate Metal-Organic Frameworks

The coordinative pliancy of the phosphonate functional group means that metal-phosphonate materials often self-assemble as well-packed structures with minimal porosity, as efficient inter-ligand packing is enabled. Here, we report a multistep synthesis of a novel aryl-phosphonate linker with an orthogonalized ligand core, 1,3,5-tris(4’-phosphonophenyl)-2,4,6-trimethylbenzene (H₆L2) designed to form more open structures. A series of crystalline metal-phosphonate frameworks (CALF-35 to -39) have been assembled by coordinating to divalent metals (Ba, Sr, Ca, Mg, Zn). H₆L2 is unable to pack efficiently and, as a consequence, yields several distinct microporous structures. The resulting structures are discussed in detail, with a focus on the solid-state packing of the sterically rigidified linker. Combined with larger cations (Sr, and Ba), H₆L2 packs in a parallel-offset manner, yielding isomorphous and microporous metal-organic frameworks (CALF-35 (Sr), and (Ba)). When coordinated to smaller metals (Ca, Mg, Zn), H₆L2 forms four new structures. Two Ca MOFs of different stoichiometry, (CALF-36 and 37) and a Mg MOF CALF-38 show narrow pores and have high selectivities for CO₂ over N₂ and CH₄. Finally, in CALF-39 (Zn), H₆L2 linkers pack in a herringbone fashion, resulting in a material with 10.9×10.1 Ų square channels. The stability of all structures was tested, and the most porous structure, CALF-39 (Zn), was found to retain its structure and gas adsorption after immersion in water over pH 3–11.     

Study of the crystal structure of binuclear boron difluoride acetylacetonate

The molecular and crystal structure of binuclear boron difluoride acetylacetonate, in which two boron chelate moieties are linked by a disulfide group, is determined. It is found that in the crystalline state, the chelate moieties are non-equivalent. The differences identified stem from the fact that molecules crystallize in pairs: two chelate ring (one from each molecule of the pair) are linked with each other by the stacking interaction. The other chelate rings of the pair do not participate in intermolecular interactions.     

THE REACTION OF DIMETHYL SULFOXIDE AND SYM-DICHLORO-BIS(2,4,6-TRICHLOROPHENYL) UREA

Abstract

Sym-dichloro-bis(2,4,6-trichlorophenyl) urea reacts explosively with dimethyl sulfoxide to yield phosgene, formaldehyde, methane, sulfur dioxide, ethylene chloride, methylene dichloride, chlorinated disulfides, and insoluble bis(2,4,6-trichlorophenyl) urea. The products, other than bis(2,4,6-trichlorophenyl) urea, are separated and characterized by means of gas chromatography and mass spectrometry. A homolytic mechanism is proposed for the reaction.     

Modeling Variability Order: A Semiparametric Bayesian Approach

In comparing two populations, sometimes a model incorporating a certain probability order is desired. In this setting, Bayesian modeling is attractive since a probability order restriction imposed a priori on the population distributions is retained a posteriori. Extending the work in Gelfand and Kottas (2001) for stochastic order specifications, we formulate modeling for distributions ordered in variability. We work with Dirichlet process mixtures resulting in a fully Bayesian semiparametric approach. The details for simulation-based model fitting and prior specification are provided. An example, based on two small subsets of time intervals between eruptions of the Old Faithful geyser, illustrates the methodology.     

Bayesian nonparametric modeling for functional analysis of variance

Analysis of variance is a standard statistical modeling approach for comparing populations. The functional analysis setting envisions that mean functions are associated with the populations, customarily modeled using basis representations, and seeks to compare them. Here, we adopt the modeling approach of functions as realizations of stochastic processes. We extend the Gaussian process version to allow nonparametric specifications using Dirichlet process mixing. Several metrics are introduced for comparison of populations. Then we introduce a hierarchical Dirichlet process model which enables comparison of the population distributions, either directly or through functionals of interest using the foregoing metrics. The modeling is extended to allow us to switch the sampling scheme. There are still population level distributions but now we sample at levels of the functions, obtaining observations from potentially different individuals at different levels. We illustrate with both simulated data and a dataset of temperature versus depth measurements at different locations in the Atlantic Ocean.