Spectral Widths in the Rate Equations for Photodesorption by Laser Infrared

1983 ◽  
Vol 29 ◽  
Author(s):  
Joachim Heidberg
Keyword(s):  
Solid Surface ◽  
Surface Interaction ◽  
Molecular Properties ◽  
Solid Surfaces ◽  
High Yield ◽  
Rate Equations ◽  
Resonant Laser ◽  
Wavelength Selectivity

ABSTRACTDesorption and evaporation from solid surfaces are induced with high yield and wavelength selectivity by excitation of internal adsorbate vibrations with resonant laser infrared. Simple rate equations describe essential features of the process and relate the photoreaction rate and yield to the intensity, the duration of laser-solid surface interaction and molecular properties of the adsorbate. The significance in photodesorption of the experimentally determined spectral widths is shown. Considering the spectral widths in the theory brings the order of the calculated photo-desorption rates for CH3 F-NaCl and the measured rates (also yields) in better concert.

scholarly journals The premolten layer of ice next to a hydrophilic solid surface: correlating adhesion with molecular properties

2017 ◽  
Vol 19 (1) ◽  
pp. 305-317 ◽  
Author(s):  
Jonathan F. D. Liljeblad ◽  
István Furó ◽  
Eric C. Tyrode
Keyword(s):  
Solid Surface ◽  
Molecular Properties

Multiple spectroscopy techniques have been used to correlate macroscopic adhesion to molecular properties of the premolten layer of ice next to silica.

On the Hysteresis of Adsorption on Solid Surfaces

1952 ◽  
Vol 5 (2) ◽  
pp. 288
Author(s):  
RG Wylie
Keyword(s):  
Phase Transitions ◽  
Solid Surface ◽  
Three Dimensional ◽  
Solid Surfaces ◽  
Two Dimensional ◽  
Capillary Effects ◽  
First Order ◽  
Adsorption Of Gases ◽  
First Order Phase ◽  
Hysteresis Phenomena

Hysteresis phenomena associated with the adsorption of gases on solid surfaces are usually explained in terms of three-dimensional capillary effects or with more or less unspecific reference to phase transitions. It is shown that hysteresis effects are to be expected when two dimensional phase transitions occur on solids. In the connection, the thermodynamic equation governing the equilibrium of small, incompressible two-dimensional phases is derived. Such phases can form on an imperfect solid surface in an irreversible manner and, as calculation shows, can contribute significantly to the hysteresis of adsorption. In some cases the phase change may be responsible for the whole effect. The diffuseness of first-order phase transitions may be due to the same mechanism.

Particle Adhesion to Solid Surfaces

1990 ◽  
Vol 33 (2) ◽  
pp. 33-37
Author(s):  
Lewis Hecht
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Solid Surface ◽  
Review Paper ◽  
Solid Surfaces ◽  
Particle Adhesion ◽  
Sources Of Information ◽  
Technical Literature ◽  
The Subject ◽  
Adhesive Forces

This review paper provides cleanroom technologists with an up-to-date overview on the subject of particle adhesion to solid surfaces. The discussion consists of four sections: (1) fundamental concepts of adhesion, (2) the nature of a solid surface, (3) the physical properties of particles, and (4) comments on the various theories of particle adhesion to solid surfaces. Some practical examples are also cited. A numeric example of adhesive forces as a function of particle size is presented in detail. The appendix contains references to other useful sources of information in the technical literature.

Adsorption Processes at Solid Surfaces-Studied by Electrokinetic Investigations

2006 ◽  
Vol 314 ◽  
pp. 19-24 ◽  
Author(s):  
Cornelia Bellmann ◽  
Anja Caspari
Keyword(s):  
Zeta Potential ◽  
Surface Chemistry ◽  
Solid Surface ◽  
Adsorption Process ◽  
Ph Value ◽  
Streaming Potential ◽  
Solid Surfaces ◽  
Multicomponent Mixtures ◽  
Adsorption Processes ◽  
Different Shapes

The process of electrophoretic deposition depends strongly on the electrokinetic properties and with it the surface properties of the material that will be processed. Different additives, conditioners but also the suspending liquid influence the surface of the applied material by adsorption. Electrokinetic investigations reflect changes in properties at the outermost solid surface very sensitive. Streaming potential measurements are especially suited for studying such changes of surface chemistry at solids with different shapes. Two approaches are applicable: 1. The adsorption process was done before measuring. The result of this process should be shown. In this case it will be interesting to see differences in the functionality of the solid surface. The zeta potential will be measured versus different pH value. 2. The adsorption process will be studied directly. The zeta potential will be determined versus the concentration of the adsorptive. The second approach can be used for investigation of adsorption of multicomponent mixtures. Competing adsorption processes are detectable.

scholarly journals Hybrid Atomistic-Continuum Simulation of Nanostructure Defect-Induced Bubble Growth

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Yijin Mao ◽  
Bo Zhang ◽  
Chung-Lung Chen ◽  
Yuwen Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Phase Change ◽  
Molecular Dynamic ◽  
Solid Surface ◽  
Bubble Growth ◽  
Molecular Level ◽  
Liquid Argon ◽  
Solid Surfaces ◽  
Solid Copper

Effects of nanostructured defects of a copper solid surface on bubble growth in liquid argon have been investigated through a hybrid atomistic-continuum (HAC) method. The same solid surfaces with five different nanostructures, namely, wedge defect, deep rectangular defect (R-I), shallow rectangular defect (R-II), small rectangular defect (R-III), and no defect were modeled at the molecular level. Liquid argon was placed on top of hot solid copper with a superheat of 30 K after equilibration was achieved with computational fluid dynamics–molecular dynamic (CFD–MD) coupled simulation. Phase change of argon on five nanostructures has been observed and analyzed accordingly. The results showed that the solid surface with wedge defect tends to induce a nanobubble more easily than the others, and the larger the size of the defect, the easier it is for the bubble to generate.

scholarly journals Recurrent Dynamics of Rupture Transitions of Single Giant Vesicles at Solid Surfaces

2020 ◽  
Author(s):  
V.N. Ngassam ◽  
W.-C. Su ◽  
D. L. Gettel ◽  
Y. Deng ◽  
Z. Yang ◽  
...  
Keyword(s):  
Solid Surface ◽  
Hydrophobic Surface ◽  
Lipid Vesicles ◽  
Thermal Fluctuations ◽  
Solid Surfaces ◽  
Contact Boundary ◽  
Lipid Phase ◽  
Giant Vesicles ◽  
Healing Phase ◽  
Pore Closure

ABSTRACTSingle giant vesicles (GVs) rupture spontaneously from their salt-laden suspension onto solid surfaces. At hydrophilic surfaces, they rupture via a recurrent burst-heal dynamics: during burst, single pores nucleate at the contact boundary of the adhering vesicles facilitating asymmetric spreading and producing a “heart” shaped membrane patch. During the healing phase, the competing pore closure produces a daughter vesicle. At hydrophobic surfaces, by contrast, the GVs rupture via a distinctly different, yet recurrent, bouncing ball rhythm: Rendered tense by the substrate interactions, GVs porate and spread monomolecular layer on the hydrophobic surface in a symmetric manner. Here too, the competition from pore closure produces a daughter vesicle, which re-engages with the substrate. In both cases, the pattern of burst-reseal events repeats multiple times splashing and spreading the vesicular fragments as bilayer patches at the solid surface in a pulsatory manner. These remarkable recurrent dynamics arise not because of the elastic properties of the solid surface but because the competition between membrane spreading and pore healing, prompted by the surface-energy dependent adhesion, determine the course of the topological transition.STATEMENT OF SIGNIFICANCEGiant lipid vesicles adhering to a solid surface experience strong mechanical stresses. The contacting membrane segment loses thermal fluctuations and accumulates mechanical tension, the equilibration of which can give rise to global shape changes, lipid phase separation, and traction forces. Beyond a threshold tension, vesicles porate, unravel, and spread. Here, we find that a competition from pore-healing can make rupture iterative, rather than a single all-or-nothing event. During burst, single pores expand, spreading a lipid bilayer on the hydrophilic surface and a monolayer on the hydrophobic one. During heal, pore-healing can produce daughter vesicles. This burst-reseal event reiterates “splashing” portions of single vesicles at the solid surface and “bouncing” the remainder as a secondary vesicle in multiple steps.

An optical method of measuring the thickness of adsorbed monolayers

1952 ◽  
Vol 212 (1111) ◽  
pp. 505-508 ◽  
Keyword(s):  
Fatty Acid ◽  
Solid Surface ◽  
Optical Method ◽  
Solid Surfaces ◽  
Acid Molecule ◽  
Fatty Acid Molecule ◽  
Monomolecular Layer ◽  
Independent Evidence ◽  
X Ray

The interferometric techniques developed by Tolansky have been used to study films adsorbed on solid surfaces. A monomolecular layer of fatty acid was spread by the retraction technique over part of a selected facet of a piece of mica. A highly reflecting layer of silver was then deposited on both sides of the mica specimen, and the thickness of the acid layer determined by multiple reflexion interferometry. The values so obtained were in agreement with X-ray data on the length of the fatty-acid molecule. Examination showed that the layers were uniform in thickness; polymolecular layers were absent. The method provides direct and independent evidence that molecules of a fatty acid, spread by the retraction technique, are adsorbed on a solid surface as a uniform monomolecular layer.

scholarly journals The interaction of atoms and molecules with solid surfaces III—The condensation and evaporation of atoms and molecules

1936 ◽  
Vol 156 (887) ◽  
pp. 6-28 ◽  
Keyword(s):  
Solid Surface ◽  
Room Temperature ◽  
Vibrational Energy ◽  
Accommodation Coefficient ◽  
Simple Relation ◽  
Solid Surfaces ◽  
Atoms And Molecules ◽  
Adsorbed Phase ◽  
Adsorbed Atoms ◽  
The Continuum

In the first two papers of this series (to be referred to as papers I and II) calculations were made of the probability that an atom adsorbed on a solid surface would be excited to states of higher vibrational energy and to states in the continuum, equivalent to evaporation. In this paper we carry the theory of evaporation a stage further and also develop a theory of condensation and show the relation of the theory to the method of statistical mechanics. Langmuir showed by a simple dynamical argument that under certain assumptions a solid surface in contact with a gas would be partially covered with adsorbed atoms and that the fraction of the surface covered could be expressed in terms of the pressure of the gas by the simple relation θ = ap /(1 + ap ). The parameter a is proportional to the product of a quantity τ, which is the average time spent by an atom in the adsorbed phase, and a quantity c , which is the probability that an atom striking the surface shall be adsorbed. Recently bowlers has shown that Langmuir's formula is essentially a thermodynamic one and can be obtained without involving a precise mechanism either of adsorption or evaporation. By adjusting the parameter a , the formula can be made to fit many of the experimental results and so the value of the product c τ can be inferred. This is probably as far as the statistical method can go. It cannot determine either c or τ uniquely, and if estimates are to be made of then information about c must be obtained from other sources. It is often assumed that c is of the order of unity, but this cannot be true in all cases, or even in the most interesting ones, for, as Roberts has shown, the accommodation coefficient (which is a measure of the probability that an atom will gain or lose energy on striking a solid surface) is sometimes very small. It is as low as 0·05 for helium striking tungsten and only 0·07 for neon striking tungsten at room temperature.

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