Papers by Michael Menzinger
The Canadian Journal of Chemical Engineering, 2015
Faraday Discussions of the Chemical Society
The Journal of Physical Chemistry
ABSTRACT
The Journal of Physical Chemistry A, 2000
Chemiluminescent reactions of ground state (Ca, Sr, and Ba) atoms with (Cl 2 , Br 2 , I 2 , ICl, ... more Chemiluminescent reactions of ground state (Ca, Sr, and Ba) atoms with (Cl 2 , Br 2 , I 2 , ICl, and IBr) were studied in a beam-gas arrangement. The MX 2 * pseudo-continua were measured as a function of target gas pressure in the 0.0001-0.25 Pa range. To identify the main reaction channels that contribute to MX 2 * formation and to obtain their relative contributions, kinetic models were fitted to the data. The following channels were considered: (1) radiative two-body recombination (R2BR), (2) radiative three-body recombination (R3BR), (3) two consecutive harpooning steps involving MX † intermediate (two-step chemiluminescent reaction TSCR), and (4) combinations of the above. On their own, none of the mechanisms (1-3) provide satisfactory data fits. The best agreement is obtained by a model involving both R2BR and TSCR. The branching ratios of these channels were determined for p) 0-0.25 Pa. At 0.16 Pa these R2BR fractions vary from 7% (for Ca, Sr + ICl) to 79% (for Ba + IBr). Absolute CL cross sections and lower limits of photon yields were estimated by cross-calibrations. Photon yields for R2BR varied from 0.0004% to 0.037%, depending on the collision partners.
Pattern Formation: Symmetry Methods and Applications, 1995
Chem Phys Lett, 1981
... 1 August 1981 CHEMI4ONIZATION EXCITATION FUNCTIONS FOR Ba + X2 = BaX+ + X-(X = F, CI): EVIDEN... more ... 1 August 1981 CHEMI4ONIZATION EXCITATION FUNCTIONS FOR Ba + X2 = BaX+ + X-(X = F, CI): EVIDENCE FOR HARPOONING Michael MENZINGER and David WREN Department of ... r-I ' 1.2 ~ Ba + F2 oe o"~, ~- 7-- o ' I , I ~ I , I 0 0.2 o.4 0.6 0.8 Collision Energy leVI --~ i ' I ...
Can J Chem, 1977
The velocity distributions of the heavy components in CD4/CH4/He(H2) supersonic beams were measur... more The velocity distributions of the heavy components in CD4/CH4/He(H2) supersonic beams were measured by time-of-flight and the slippage with respect to the seeding gas was investigated as a function of nozzle pressure and temperature. The isotopic species attain different velocity distributions. Following a proposal by Anderson and Davidovits, isotope separation factors are calculated both for the present system and, by analogy, for 235UF6/238UF6/Ar(He,Xe).
Physical Review E Statistical Physics Plasmas Fluids and Related Interdisciplinary Topics, 1999
A recent prediction of stationary waves in open, reacting flows is experimentally verified. We sh... more A recent prediction of stationary waves in open, reacting flows is experimentally verified. We show that stationary waves are generated by a mechanism whereby the flow carries a time-oscillating subelement, behaving like a batch reactor, through space while a fixed boundary condition at the inflow locks the phase of the oscillation. This mechanism can generate stationary patterns when all diffusion coefficients are equal. The experimental system is the ferroin-catalyzed Belousov-Zhabotinsky reaction in a tubular reactor, fed by the outflow of a continuous flow stirred tank reactor (CSTR). Parameter conditions are such that the concentrations are constant in the CSTR while they oscillate in the flow tube.
Journal of Physical Chemistry, 1990
Can J Chem, 1983
Absolute chemiluminescence and quenching (beam attenuation) cross sections were measured for the ... more Absolute chemiluminescence and quenching (beam attenuation) cross sections were measured for the title reactions in a beam/gas experiment. In the Ca* + NO2 system, both quantities are about twice as large as in the N2O reaction. The chemiluminescence quantum yields, corrected for infrared emission from the A1Σ+ and A′ 1Π states, are of similar magnitude YCL(Ca* + N2O) = 7.2 ± 1.1% and YCL(Ca* + N2O) = 8.0 ± 0.9%. The quenching cross sections are στ(Ca* + N2O) = 153 ± 32 Å2 and στ(Ca* + N2O) = 73.2 ± 5.7 Å2, consistent with a long-range harpooning process in the former and an electron transfer at closer range for the latter system. The partial resolution of CL spectra was aided by lifetime-separated spectroscopy. The principal emitter in both systems is the long-lived CaO(A′ 1Π), next to minor yields of CaO in the short-lived A1Σ+, B1Π, and "orange and green arc band" states. The results are discussed in light of adiabatic correlations. The arc states are argued to arise in nearly coplanar collisions from the rearrangement of an excited intermediate. An information theoretical analysis reveals considerable dynamical bias in the form of non-linear surprisal plots.
Can J Chem, 1974
Electronic chemiluminescence has been observed for nine reactions of Group IIa metal atoms (M = C... more Electronic chemiluminescence has been observed for nine reactions of Group IIa metal atoms (M = Ca, Sr, Ba) with dihalogen molecules (X2 = F2, Cl2, Br2).In all cases one or more electronically excited states of the monohalide MX* were observed. Continuum emission, presumably due to dihalides MX2*, was seen in all systems, and the emission intensity increased in the order F2
We examine numerically the storage capacity and the behaviour near saturation of an attractor neu... more We examine numerically the storage capacity and the behaviour near saturation of an attractor neural network consisting of bistable elements with an adjustable coupling strength, the Bistable Gradient Network (BGN). For strong coupling, we find evidence of a first-order "memory blackout" phase transition as in the Hopfield network. For weak coupling, on the other hand, there is no evidence of such a transition and memorized patterns can be stable even at high levels of loading. The enhanced storage capacity comes, however, at the cost of imperfect retrieval of the patterns from corrupted versions.
Physical Review E Statistical Nonlinear and Soft Matter Physics, 2003
We examine numerically the storage capacity and the behaviour near saturation of an attractor neu... more We examine numerically the storage capacity and the behaviour near saturation of an attractor neural network consisting of bistable elements with an adjustable coupling strength, the Bistable Gradient Network (BGN). For strong coupling, we find evidence of a first-order "memory blackout" phase transition as in the Hopfield network. For weak coupling, on the other hand, there is no evidence of such a transition and memorized patterns can be stable even at high levels of loading. The enhanced storage capacity comes, however, at the cost of imperfect retrieval of the patterns from corrupted versions.
The Journal of Physical Chemistry, 1990
ABSTRACT
The Journal of Physical Chemistry, 1986
The Journal of Physical Chemistry, 1986
... Recent studies of chemical bistability in continuously stirred tank reactors (CSTR) showed th... more ... Recent studies of chemical bistability in continuously stirred tank reactors (CSTR) showed that the rate of stirring can play a hitherto unsuspected and ... We shall now consider how mixing and reaction can couple in a nonideal CSTR to produce the observed stirring effects in the ...
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Papers by Michael Menzinger