No abstract

Cyanine dyes (1a–d) with the 5,5′,6,6′‐tetrachloro‐1,1′‐dialkyl‐3,3′‐di‐(3‐carboxypropyl)‐benzimidocarbocyanine chromophore differing only in the chain length of their alkyl groups in 1,1′‐position have been synthesized, spectroscopically characterized, and compared with 5,5′6,6′‐tetrachloro‐1,1′‐diethyl‐3,3′‐di‐(4‐sulfobutyl)‐benzimidocarbocyanine(TDBC). In aqueous solution the dyes form J‐aggregates which, depending on the alkyl group chain length, exhibit J‐bands differing in spectral positions, bandwidth, and in the number of peaks.

ZUSCHRIFTEN 1.078 9 A@ (298) = 123.9 kcal mol-' p = 0 83 Debye J 1.086 Zusammcnfxsend liiljt sich feststellen, daW wir nwtu-Dchydrobenzol ails zwei Vorstufen crzeugen und erstmals spekuoskopisch charaktcrisicrcn konnten. Die ausgczcichncte ijbereinstimmung zwischen experimentellen und bcrcchneten IK-Spcktren zcigt deutlich. dalj IK-Spektren von Diradikalen mit nicht zu hohem Multirefcrcn/charakter auf CCSD(T)-Niveau niit hoher Gcnauigkeit berechnet werden kbnncn. Eingegangcn am 2. November I995 !/, 85201 Stichworte: Ab-initio-Rechnungen * 1.3-Didehydrobcnzol * Diradikalc: Phoiolyse * Thermolysc [ I ] a ) J. (i Radzis7e\vski. A. A .

The spectroscopic properties of a J-aggregating cyanine dye in the presence of betainic N-n-alkyl-N,N-dimethylammonio acid bromides with alkyl chain lengths between 10 and 16 carbon atoms are examined. In contrast to the usually observed deaggregating influence of micelle-forming agents, an increase in absorptivity and a decrease in J-band width are established. Furthermore, the spectroscopic properties of the J-band depend on the N-n-alkyl chain length of the surfactant. The coupling size of the aggregates increases in surfactant solution as compared to that in aqueous solution. The effects are attributed to a new type of supramolecular structure based on J-aggregates with enclosed monomer molecules of the surfactant.

From measurements of the cross sections for eẽ-~hadrons and the cross sections and forward-backward charge-asymmetries for e e-~e + e-,~+-and s-r at several centreof-mass energies around the Z" pole with the DELPHI apparatus, using approximately 150000 2 = 0.0003±0.0010and A~= 0.2508±1)0027. These values correspond to the electroweak parameters: PCV = 1.003±0.011and sin20~j 0.241±0.009.Within the Minimal Standard Model (MSM). the results can he expressed in terms of a single parameter: sin20~=0.2338±0.0027.All these values are in good agreement with the predictions ot the MSM. Fits yield 43< m 115, < 215 0eV at the 95Vr level. Finally, the measured values of "z and arc used to derive lower mass bounds for possible new particles. * The VD, which was operated during most of the 1990 data collection period, was used in the alignment procedure of the barrel tracking detectors, but was not used directly in the analysis described here. * Fits with the formula of ref. [26] tend to underestimate M~and T~by about 2 MeV and to overestimate a'1~by approximately 0.1%.