Papers by Stephen E Bialkowski
The Journal of Chemical Physics, 1978
A CO2 TEA laser has been used to initiate the collisionless multiphoton dissociation of CH3OH bet... more A CO2 TEA laser has been used to initiate the collisionless multiphoton dissociation of CH3OH between 1000 and 10 mtorr. The appearance of OH(X 2Πi) 50±20 nsec after the laser pulse, independent of initial CH3OH pressure (50–200 mtorr), suggests the primary dissociative channel CH3OH+nhν→CH3 +OH(X 2Πi); although CH3 could not be correspondingly confirmed. The appearance of CH(X 2Πr) 70±20 nsec after the OH(X) appearance, independent of initial CH3OH pressure (70–400 mtorr), suggests secondary collisionless dissociation. Initial rovibronic distributions of OH(X) and CH(X) were determined, as well as characteristic decay time constants. The observation of the relaxation of OH(X) over a 10 μsec time interval after radical onset, allowed the separate characterization of collisional rotational relaxation and translational diffusion.
The Journal of Chemical Physics, 1977
CO2 TEA laser has been used to initiate the multiphoton dissociation of CH3OH, both pure and with... more CO2 TEA laser has been used to initiate the multiphoton dissociation of CH3OH, both pure and with NO added as a free radical scavenger. The decomposition of CH3OH at the high power density of the focused laser radiation results in molecular and free radical initiated products. Decomposition through molecular intermediates appears to proceed via CH3OH+nhν→CH2O*+H2 and CH2O* →CO+H2, and comprises ∼90% of the consumed CH3OH in ∼3000 laser pulses. The radical initiated process CH3OH+nhν→CH3 +OH ultimately results in the stable products C2H4, C2H2, and CH4 to an extent of ∼10% of the CH3OH consumed. Luminescence from the focal zone is due to emission from OH†, CH†, C†2, and possibly CH2O†. Stable products as well as the visible luminescence due to the electronically excited diatomic radicals are followed as a function of pressure, time, and addition of the free radical scavenger gas NO. Both major photodecomposition routes appear to be non-Boltzmann.
Chemical Physics Letters, 1982
The vrbrational relaxauon dynamics of the ground '$ electronic start oiCJ has been studied iollo~... more The vrbrational relaxauon dynamics of the ground '$ electronic start oiCJ has been studied iollo~rng IR mulrrple photon diiociatron of aknc. Wavelength and trmc resolved spectra, using dye laser-Induced ~luorcsccncc arc used to charactetue the vibrational levels and Iheir CorKspondfflP nse and decay rates. \'rbratronal rclaxrlion rates arc rcportcd for+ C3(' $. 100 or 1 IO) in the presence of Ar. He, Nz. 0:. and CzHz, rn addrtron to the reactron raw constant of C~('~,.@OO) nirh CzH2 of(Z.2 f 0 10) X ICI-" cm3 molecule-' s-'.
Wavelength-Modulated Photoacoustic Spectroscopy
IUPAC Standards Online, Mar 14, 2016
Optothermal Window
IUPAC Standards Online, Mar 14, 2016
Optical Pyrometry
IUPAC Standards Online, Mar 14, 2016
Depth Profiling
IUPAC Standards Online, Mar 14, 2016
Photoinduced Acoustic SpectroscopyC. K. N. Patel and A. C. Tam. Rev. Mod. Phys. 53, 517 (1981). J. A. Sell (Ed.). Photothermal Investigations of Solids and Fluids, Academic Press, London (1989). S. E. Braslavsky and G. E. Heibel. Chem. Rev. 92, 1381 (1992). S. E. Bialkowski. Photothermal Spectros...
IUPAC Standards Online, Mar 14, 2016
Stimulated Light Scattering
IUPAC Standards Online, Mar 14, 2016
Acoustic Transit Time
IUPAC Standards Online, Jan 14, 2016
Multiphoton Absorption
IUPAC Standards Online, Mar 14, 2016
Transmission Grating Signal
IUPAC Standards Online, Mar 14, 2016
Thermoluminescence
IUPAC Standards Online, Mar 14, 2016
Radiative Rate Constant
IUPAC Standards Online, Mar 14, 2016
Raman Scattering
IUPAC Standards Online, Mar 14, 2016
Analytical Chemistry, Oct 1, 1990
In a recent paper Bialkowski (1) derived formulas for computing maximum likelihood estimates (MLE... more In a recent paper Bialkowski (1) derived formulas for computing maximum likelihood estimates (MLEs) for the most probable values of shot noise limited signals using both Poisson and Gaussian probability density functions. Surprisingly the estimators for these two distributions differed significantly despite the fact that function magnitude MLEs were equivalent for the two models. The Gaussian model was formulated so that signal variance was equal to its most probable value. This is inherent in the Poisson formula and accomplished in the Gaussian model by substituting the mean for the variance. While these assumptions are true in describing the photon flux from a thermal source, noise sources in a photomultiplier tube can increase the variance of the recorded signal significantly. Noise in PMT currents is composed of many factors in addition to the noise in the photon flux including photocathode quantum efficiency (2) and nonuniformity as well as variations in dynode uniformity. Partially offsetting these, the bandwidth of the measurement system can reduce the recorded variance of the signal. As a result the variance of PMT signals is proportional to current but not necessarily equal to it. Inclusion of this fact into Bialkowski's derivation shows the equivalence of most probable values for Poisson and Gaussian models.
Experimental Studies of Liquid Behaviour in Partially Saturated Angular Pore Micromodels
AGU Fall Meeting, 2000
Front-Face-Excitation Photoacoustic Signal
IUPAC Standards Online, Mar 14, 2016
Optical Heterodyne Detection (OHD) (of a Grating Signal)
IUPAC Standards Online, Mar 14, 2016
Elastic Heat Wave
IUPAC Standards Online, Mar 14, 2016
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Papers by Stephen E Bialkowski