Molecule in a strong quasi-monochromatic light

Quasi-energies are calculated for a system containing two nondegenerate electronic terms interacting with a one-dimensional harmonic oscillator. The energetic structure of such model of a molecule is shown to have quasi-intersections connected with the appearance of new adiabatic surfaces in a strong light field. In the vicinity of a quasi-intersection sharp changes of a molecular wave function, dipole moment and inversion take place.     

Temperature and pressure effects on the far I.R. spectra associated with liquid lattices

The low frequency (10–150 cm^?1) infrared absorptions of selected polar liquids (acetonitrile, t-butyl cyanide, acetone and pivalone) as a function of pressure, temperature and also concentration in a non-polar solvent (CCl₄) have been investigated using a variable-temperature variable-pressure cell, linked with a non-dispersive Michelson interferometer.     

Equidissections of centrally symmetric octagons

Summary In 1970 Monsky proved that a square cannot be cut into an odd number of triangles of equal areas. In 1988 Kasimatis proved that if a regularn-gon,n 5, is cut intom triangles of equal areas, thenm is a multiple ofn. These two results imply that a centrally symmetric regular polygon cannot be cut into an odd number of triangles of equal areas. We conjecture that the conclusion holds even if the restriction regular is deleted from the hypothesis and prove that it does forn = 6 andn = 8.     

The interaction of sodium caseinate with monoglyceride and diglyceride at the oil-water interface and its effect on interfacial rheological properties

The viscoelasticity at a corn oil-water interface of films of sodium caseinate, and of sodium caseinate plus glyceryl monostearate (GMS) and glyceryl distearate (GDS), have been examined. Caseinate films exhibited little viscoelasticity, but in the presence of GMS and GDS significant viscoelasticity developed. The magnitude of the viscoelasticity parameters was influenced by the GMS/GDS ratio employed at any caseinate concentration. Optimum values of the parameters were obtained at a 5/2 GMS/GDS ratio. This was attributed to association of caseinate with the glycerides, which had themselves entered into some form of association prior to adsorption of caseinate.     

Low temperature 13C NMR magnetic resonance in solids 4. Cyclopropane,bicyclo[1.1.0]butane and [1.1.1] propellane

The solid state ¹³C NMR spectra of bicyclo[1.1.0]butane and [1.1.1]propellane have been measured at low temperature. The orientation of the principal axes of the chemical shielding tensor have been determined with ab initio calculations based on the IGLO (Individual Gauge for Localized Orbitals) method when they are not determined by symmetry. Excellent agreement is obtained between the calculated and experimental principal values of the shielding tensor when basis sets containing polarization functions are used. In most cases the agreement is such that the calculated values are within the experimental error.Part 3 of this series: Ref. [7]     

Aquametric microdetermination of hydration of ion-exchange resins

An aquametric microtechnique is proposed for measuring the pre-adsorbed (residual) moisture (DeltaW) and equilibrium moisture content (H) in macroporous weakly basic anion-exchangers and their gel analogues, during the derivation of water-vapour sorption isotherms by use of a modified McBain balance in a vacuum system. The absolute values of DeltaW and H are determined by direct Karl Fischer titration of weighed samples of the anion-exchanger after equilibrium hydration has been achieved at various relative water-vapour pressures (P/P(s). The relationship between DeltaW and the sample pretreatment conditions, characteristics of the polymer matrix (basicity and porosity), and the nature of the ionogenic groups in the ion-exchanger has been established. It has been shown that the hydration parameters, in terms of the BET theory and specific anion-exchanger surface area depend largely on DeltaW. For instance, in the case of the strongly basic anion-exchangers AB-171 and AB-17-8. which contain quaternary ammonium groups, the degree of hydration in the BET region may be well in excess of the apparent effective capacity (h) of the BET monolayer. It has been shown that the specific surface area for water (S(H(2)O), calculated from aquametric isotherms by using the BET equation, corresponds to the hydrophilic anion-exchanger surface area, as compared to the SH(2)O value calculated from gravimetric isotherms.     

Semiconductor nanoparticle/polystyrene latex composite materials

Cadmium sulfide and cadmium selenide/cadmium sulfide core/shell nanoparticles stabilized with poly(cysteine acrylamide) have been bound to polystyrene (PS) latexes by three methods. First, anionic 5 nm diameter CdS particles were electrostatically attached to 130 nm surfactant-free cationic PS latexes to form stable dispersions when the amount of CdS particles was less than 10% of the amount required to form a monolayer on the surface of the PS particles or when the amount of CdS particles exceeded the amount required to form a monolayer on the PS particles. Transmission electron microscopy (TEM) showed nanoparticles on the surface of the latex particles. Fluorescence spectra showed unchanged emission from the nanoparticles. Second, anionic, surfactant-free PS latexes were synthesized in the presence of CdS and CdSe/CdS nanoparticles. TEM showed monodisperse latex particles with trapped nanoparticles. Third, surfactant-stabilized latexes were synthesized by copolymerization of styrene with vinylbenzyl(trimethyl)ammonium chloride electrostatically bound to the CdSe/CdS nanoparticle surface. Brownian motion of the submicroscopic composite particles in water was detected by fluorescence microscopy.     

Synthesis and characterization of a disulfide-linked c(5)-symmetric [5]carceplex.

The synthesis and characterization of the first disulfide-linked and C5-symmetric carceplex.(guests)2 using the recently described [5]cavitands as building blocks is reported. The solution behavior of the new carceplexes was explored by 1D NOSEY (EXSY) experiments. The disulfides have unusually high energy barriers to interconversion due to their cooperativity. The guests (2 DMF or 2 DMA) reside in an unusual orientation in parallel planes that are perpendicular to the principal axis of the host.