Ferrocene polymers. Synthesis and thermal polymerization of α-chloro-β-formyl-p-ferrocenylstyrene

The synthesis and thermal polymerization of a new chloroformylated vinyl derivative containing a ferrocenyl residue are reported.The reactivity of α-chloro-β-formyl-p-ferrocenylstyrene in the polymerization reaction is discussed in the light of the experiment results and data obtained from molecular orbital calculations using the Hückel approximation.     

Submillimeter spectroscopy of the major isotopes of water

Extensive new measurements in the region 300–1100 GHz for the major isotopes of water in both the ground and first excited vibrational states are reported. These results are used as the basis for centrifugal distortion analyses of these species that are based solely upon microwave data. Comparisons are made with both earlier microwave work and with previous analyses based upon weighted data sets of microwave and high-resolution infrared data. The new measurements reported in this paper represent more than a third of the total microwave data currently available.     

Microwave spectrum and substitutional structure of CH2DF

Forty-two transitions of the microwave spectrum of CH₂DF have been observed in the region between 75 and 450 GHz. The measurement of both a-type and b-type transitions makes possible the analysis of the spectrum and the accurate calculation of the rotational constants (in MHz): = 119 675.0535 ± 0.074, = 24 043.4415 ± 0.072, ? = 22959.3732 °0.072, °j = 0.049371 ±0.00011, °_jk = 0.34268 ±0.0006, 2_k = 3,3774 ± 0.0035, δ _j = 0.002329 ± 0.000045, δ_k = 0.0687 ± 0.036. These constants, in combination with the results of earlier work on the symmetric speci r_s structure calculation based entirely on high-accuracy microwave data. The structural parameters are r_CH = 1.100 Å, r_CF = 1.383 Å, and ∠HCH = 110° 37'.     

On mixtures of distributions of Markov chains

Let X be a chain with discrete state space I, and V be the matrix of entries V_i,n, where V_i,n denotes the position of the process immediately after the nth visit to i. We prove that the law of X is a mixture of laws of Markov chains if and only if the distribution of V is invariant under finite permutations within rows (i.e., the V_i,n's are partially exchangeable in the sense of de Finetti). We also prove that an analogous statement holds true for mixtures of laws of Markov chains with a general state space and atomic kernels. Going back to the discrete case, we analyze the relationships between partial exchangeability of V and Markov exchangeability in the sense of Diaconis and Freedman. The main statement is that the former is stronger than the latter, but the two are equivalent under the assumption of recurrence. Combination of this equivalence with the aforesaid representation theorem gives the Diaconis and Freedman basic result for mixtures of Markov chains.     

Intramolekulare diels-alder-reaktionen mit substituierten 1,2,4,5-tetrazinen und 1,2,4-triazinen

1,2,4,5-tetrazines as well as 1,2,4-triazines carrying sidechain dienophiles react in an intramolecular Diels-Alder cycloaddition with inverse electron demand to yield novel bicyclic pyridazines and pyridines.     

Inelastic light scattering in highly excited GaAs

The coupled plasmon-LO-phonon and single-particle excitations of a photocreated electron-hole plasma in high purity GaAs are studied by means of Raman scattering measurements. The experimental results are described by the random-phase approximation with respect to the multicomponent character of optical plasma. From single-particle spectra the plasma distribution function and drift velocities up to 10⁷ cm/s have been determined. Using the coupled modes as probe for the plasma density the temperature dependence of the recombination in the EHP is studied.     

Prediction and assignment of the FIR spectrum of hydrogen peroxide

Millimeter and submillimeter microwave studies are used to predict and assign the FIR rotational-torsional spectrum of hydrogen peroxide. Special attention is given to the strong Q-branch features that have recently been used by Traub and Chance to place an upper limit on the atmospheric abundance of hydrogen peroxide. In addition, 67 new transitions are reported in the 400–1000 GHz region.