摘要:

AbstractThe preparation of gaseous isoselenocyanic acid, HNCSe, first reported by Landsberg [10] in 1979, has been considerably improved. This unstable molecule decays in the gaseous phase according to a second‐order reaction. In the infrared region the vibrational spectrum of HNCSe was measured in the gaseous phase and in an argon matrix at low resolution. The combined analysis of the vibrational spectra of HNCSe yielded the assignment of the A fundamental vibrations. From the gaseous phase absorptionsv4= 3535 cm−1,v2= 1957 cm−1andv3= 625 cm−1could be assigned. The bands in the gas phase spectrum at 760, 583, 521 and 419 cm−1cannot be considered as band centers. They are the result of the superposition of the subband structures of the bending modesv4,v5andv6exhibiting quasilinear behaviour. This can be deduced from the wavenumber positions ofv4= 508 cm−1andv5= 419 cm−1observed in the argon matrix spectra. Due to the rapid H/D exchange the infrared spectrum of DNCSe could no

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880503

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractThe rotational a‐type spectra of the five most abundant isotopomers of HNCSe were recorded in natural abundance. Using Watson's S‐reduced Hamiltonian the rotational and some centrifugal distortion constants could be determined for the ground vibrational state of the various isotopic species. With the aid of these constants the restructure of HNCSe could be refined and the parameter specifying the quasilinearity of the molecule could be estima

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880504

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractDiffusion coefficients and thermal diffusion factors are reported for several binary systems of carbon monoxide and oxygen with noble gases. Using approximate spherical potential functions, most of which have been reported in the literature, the experimental results are compared with the predictions of the Chapman‐Enskog theor

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880505

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractIn this paper it is shown that various results on the effect of solutes and temperature on the formation of positronium in polar solvents can be better explained by a hybrid model between the “Ore‐gap” model and the “spur” model, stating that both contribute to the formation of positronium but the inhibition in case of partial inhibitors as well as the enhancement is due only to the second model. Complete inhibition is explained as due to the removal of positronium by its oxidation rather than preventing its

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880506

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractThe reactionwas studied at room temperature in an isothermal discharge flow system. CH2‐radicals were produced either in a microwave discharge of CH2CO highly diluted in Helium or via the reaction O + CH2CO → CH2+ CO2. The CH2‐concentration was measured by laser magnetic resonance. From the pseudo first order decay of CH2in the presence of a large excess of oxygen the rate constant for reaction (1) was found

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880507

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractThe reactionwas investigated at room temperature in an isothermal discharge flow reactor with laser magnetic resonance detection of CH2and CH. Direct measurements of the decay of CH2in the presence of an excess of H‐atoms yielded a rate constant ofCombined with the known rate constant for the reverse reaction CH + H2+ CH2+ H the heat of formation of CH2was found to

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880508

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractThe rate constants (2k) for the second‐order self‐termination reaction of the N‐hydropyridinyl radical have been measured by time‐resolved ESR during intermittent UV photolysis of pyridine in various solvents containing propanol(‐2). The frequency factor and the activation energy are (1.8 ± 0.4) · 1010M−1s−1and (10.7 ± 0.4) kJ · mol−1, respectively, in propanol(‐2)/acetone (1:1 by volume) as obtained from the Arrhenius plot of 2 A: in the temperature range between 293 and 230 K. The rate constants at 285 K are (7 ± 1) · 108M−1s−1in H2O/propanol(‐2)/acetone (2:1:1 by volume), independent of the pH value (7.5 – 13.7), and (6 ± 1) · 108M−1s−1in neat propanol(‐2), the latter value being essentially diffusion controlled. The rate constants measured in propanol(‐2)/acetone (1:1) containing various amounts of water correlate with Kosower's solvent polarity parameter. The self‐termination reaction ultimately leads to the destruction of the pyridine ring. Finally, a model is presented for the correction of the influence of non‐uniform radical concentration on apparent values of second‐order rate constants as determined by t

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880509

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractIn a mixture of solvents S1and S2a cation Mz+forms “solvatomers” of the type M(S1)i(S2)k‐iz+, wherekis the coordination number of the cation andi= 0 tok.The rate of substitution of a solvating molecule by a ligand LzLdepends in general on the specific solvatomer and on the solvent molecule being substituted. – Kinetic measurements are reported on systems with the cations Be2+, Al3+, and Ni2+, the ligands sulfate, rhodanide and acetate and the solvent pairs water‐dimethylsulfoxide, water‐N‐methylformamide, water‐hexamethylphosphoric triamide, water‐formamide and methanol‐dimethylsulfoxide. – Some rules concerning the kinetic behaviour of such systems have been developed. In particular, an explanation is presented for the different kinetics observed with tetrahedrally coordinated complexes (k= 4) and with octahedrally co

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880510

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractThe electrical conductivity, the magnetic susceptibility, and the thermoelectric power of the liquid Ag – TlTe system have been obtained, respectively, as a function of temperature and composition from near the liquidus temperature up to about 900°C. These mixtures exhibit a sharp decrease in electrical conductivity and a change in sign of thermoelectric power around the stoichiometric composition AgTlTe. Measurements of magnetic susceptibility also indicate a marked anomaly at this composition. These electronic properties for the molten Ag – TlTe system are discussed in the light of current transport theories employed in the amorphous and liquid semiconduc

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880511

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY

摘要:

AbstractSolvent activities of seven organic solvents in mixtures with PDMS (Polydimethylsiloxane) of different molecular weights have been measured at 298.15 and 313.15 K using the vapor sorption technique. The results have been used for testing the thermodynamic consistency of an extended version of Flory's theory. In this theoretical approach a more detailed expression of the combinatorial entropy is used and found to be superior to the common Flory‐Huggins expressio

ISSN:0005-9021    

DOI:10.1002/bbpc.19840880512

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1984

数据来源: WILEY