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Full-Text Articles in Physical Sciences and Mathematics

Using Higher Ionization States To Increase Coulomb Coupling In An Ultracold Neutral Plasma, M. Lyon, Scott D. Bergeson, A. Diaw, M. S. Murillo Jan 2015

Using Higher Ionization States To Increase Coulomb Coupling In An Ultracold Neutral Plasma, M. Lyon, Scott D. Bergeson, A. Diaw, M. S. Murillo

Faculty Publications

We report measurements and simulations of the time-evolving rms velocity distribution in an ultracold neutral plasma. A strongly coupled ultracold neutral Ca+ plasma is generated by photoionizing laser-cooled atoms close to threshold. A fraction of these ions is then promoted to the second ionization state to form a mixed Ca+-Ca2+ plasma. By varying the time delay between the first and the second ionization events, a minimum in ion heating is achieved. We show that the Coulomb strong-coupling parameter Γ increases by a factor of 1.4 to a maximum value of 3.6. A pure Ca2+ plasma …


Time-Resolved Studies Of Ultracold Ionizing Collisions, Scott D. Bergeson, C. Orzel, S. Kulin, S. L. Rolston Jan 1998

Time-Resolved Studies Of Ultracold Ionizing Collisions, Scott D. Bergeson, C. Orzel, S. Kulin, S. L. Rolston

Faculty Publications

Using 40 ns laser pulses, we probe the real-time dynamics of ultracold ionizing collisions in metastable xenon. We time resolve both shielding and enhancement effects, and observe the production of Xe2^+ molecular ions through associative ionization. We estimate the rate of molecule formation in excited-state collisions, and directly measure the role of both flux enhancement and excited state survival in the collisional enhancement process. Conceptually simple theoretical models are used to predict the dynamics of the collisional shielding.


A Potentiometric Method, A Convenient And Rapid Technique For Determination Of The Thermodynamics Of Ionization Reactions For Water, Weak Acids, And Some Slightly Soluble Salts In Aqueous Organic Mixed Solvents, Charanai Panichajakul Aug 1976

A Potentiometric Method, A Convenient And Rapid Technique For Determination Of The Thermodynamics Of Ionization Reactions For Water, Weak Acids, And Some Slightly Soluble Salts In Aqueous Organic Mixed Solvents, Charanai Panichajakul

Theses and Dissertations

A potentiometric method which is devised to be rapid and convenient for determining ionization constants for water, weak acids (or bases), and certain solids in mixed solvents is described. The method has been applied to the determination of ionization for water, acetic acid, benzoic acid, and phenol and the solubility product constant for silver chloride in mixtures of water with methanol, ethanol, acetone, tetrahydrofuran, and p-dioxane containing from 0 to 70 mass percent organic co-solvent at several temperatures between 10 and 40°C. Results are used to study the thermodynamics of ionization in each mixture which is discussed relative to various …


Thermodynamics Of Proton Ionization In Aqueous Solution I. A Precision Thermometric Titration Calorimeter ; Ii. Entropy Titration : A Calorimetric Method For Equilibrium Constant Determinations ; Iii. H And S Values For Carboxylic Acid Proton Ionization At 25c ; Iv. Site Of Proton Ionization From Adenosine, Lee D. Hansen Aug 1965

Thermodynamics Of Proton Ionization In Aqueous Solution I. A Precision Thermometric Titration Calorimeter ; Ii. Entropy Titration : A Calorimetric Method For Equilibrium Constant Determinations ; Iii. H And S Values For Carboxylic Acid Proton Ionization At 25c ; Iv. Site Of Proton Ionization From Adenosine, Lee D. Hansen

Theses and Dissertations

The design, construction, and calibration of a precision thermometric titration calorimeter is described. This calorimeter was tested by determining the enthalpy change for ionization of water. The result, 13.34 ±0.03 kcal/mole (standard deviation), is in exact agreement with the best literature values. This standard deviation indicates that, using this calorimeter, ΔH values can be determined with an accuracy of ±0.0.5 kcal/mole. A calorimetric procedure has been developed for the, simultaneous determination of the equilibrium constant, the enthalpy change, and the entropy change for a chemical reaction from a single titration (Entropy Titration). This procedure has been tested by determining pK, …