Pressure dependence of diffusion coefficient and orientational relaxation time for acetonitrile and methanol in water: DRISM/mode-coupling study

We present results of theoretical description and numerical calculation of the dynamics of molecular liquids based on the Reference Interaction Site Model / Mode-Coupling Theory. They include the temperature-pressure(density) dependence of the translational diffusion coefficients and orientational relaxation times for acetonitrile and methanol in water at infinite dilution. Anomalous behavior, i.e. the increase in mobility with density, is observed for the orientational relaxation time of methanol, while acetonitrile does not show any deviations from the usual. This effect is in qualitative agreement with the recent data of MD simulation and with experimental measurements, which tells us that presented theory is a good candidate to explain such kind of anomalies from the microscopical point of view and with the connection to the structure of the molecules.Comment: 10 pages, 2 eps-figures, 3 table

Fast calculation of thermodynamic and structural parameters of solutions using the 3DRISM model and the multi-grid method

In the paper a new method to solve the tree-dimensional reference interaction site model (3DRISM) integral equations is proposed. The algorithm uses the multi-grid technique which allows to decrease the computational expanses. 3DRISM calculations for aqueous solutions of four compounds (argon, water, methane, methanol) on the different grids are performed in order to determine a dependence of the computational error on the parameters of the grid. It is shown that calculations on the grid with the step 0.05\Angstr and buffer 8\Angstr give the error of solvation free energy calculations less than 0.3 kcal/mol which is comparable to the accuracy of the experimental measurements. The performance of the algorithm is tested. It is shown that the proposed algorithm is in average more than 12 times faster than the standard Picard direct iteration method.Comment: the information in this preprint is not up to date. Since the first publication of the preprint (9 Nov 2011) the algorithm was modified which allowed to achieve better results. For the new algorithm see the JCTC paper: DOI: 10.1021/ct200815v, http://pubs.acs.org/doi/abs/10.1021/ct200815

Ionic liquids at electrified interfaces

Until recently, “room-temperature” (<100–150 °C) liquid-state electrochemistry was mostly electrochemistry of diluted electrolytes(1)–(4) where dissolved salt ions were surrounded by a considerable amount of solvent molecules. Highly concentrated liquid electrolytes were mostly considered in the narrow (albeit important) niche of high-temperature electrochemistry of molten inorganic salts(5-9) and in the even narrower niche of “first-generation” room temperature ionic liquids, RTILs (such as chloro-aluminates and alkylammonium nitrates).(10-14) The situation has changed dramatically in the 2000s after the discovery of new moisture- and temperature-stable RTILs.(15, 16) These days, the “later generation” RTILs attracted wide attention within the electrochemical community.(17-31) Indeed, RTILs, as a class of compounds, possess a unique combination of properties (high charge density, electrochemical stability, low/negligible volatility, tunable polarity, etc.) that make them very attractive substances from fundamental and application points of view.(32-38) Most importantly, they can mix with each other in “cocktails” of one’s choice to acquire the desired properties (e.g., wider temperature range of the liquid phase(39, 40)) and can serve as almost “universal” solvents.(37, 41, 42) It is worth noting here one of the advantages of RTILs as compared to their high-temperature molten salt (HTMS)(43) “sister-systems”.(44) In RTILs the dissolved molecules are not imbedded in a harsh high temperature environment which could be destructive for many classes of fragile (organic) molecules

Two Decades of Neptune Theatre

This article traces the changing fortunes of the Neptune Theatre, Halifax, Nova Scotia, under five artistic directors between its beginnings in 1963 and 1983. Cet article suit les fortunes changeantes du Neptune Theatre, Halifax, Nova Scotia, pendant les résidences des cinq metteurs en scène de 1963 a 1983

The composition and work of the Royal Council, in the reign of Henry II, 1154-1189

The material used, with the exception of the Carte Antique in the Public Record Office, consists entirely of printed sources and secondary works. The sources are of two kinds: firstly, biographies and chronicles; and secondly, collections of charters, letters, and constitutional documents. The two sections of the thesis correspond to the title, one dealing with the composition, the other with the work of the council. The first part discusses the relationship between the great feudal councils and the king's permanent advisory staff. As far as the great feudal councils are concerned, the thesis consists primarily in an attempt to reconcile the various accounts given in secondary works, with certain additional facts and inferences derived from the original sources. The part dealing with the perpetual advisory group shows the change from the king's almost complete reliance on the counsels of individuals at the beginning of the reign, to an almost entirely official group at the end. There are also notices of the inter-relationship of the more prominent counsellors; and the relative use of new men and members of old-established families. The second part of the thesis considers the work of the council, in four aspects: counsel, legislation, finance, and justice. The first of these deals with the question whether the king required counsel, automatic consent, or considered consent and the last with the place of feudal justice in the council in relation to the judicial and legal developments of the reign. There are also notices of the frequency, regularity, and place of meetings; and of the character of the council and court.<p

The solution to the reference hypernetted-chain approximation for fluids of hard spheres with dipoles and quadrupoles with application to liquid ammonia

This thesis is divided into two parts. In Part A the reference hypernetted-chain (RHNC) approximation is solved for a fluid of hard spheres with embedded point dipoles and linear quadrupoles. The thermodynamic properties, the dielectric constant, ∈, and the pair correlation function are compared with previously calculated Monte Carlo data as well as with results from other integral equation methods. The RHNC is found to closely approximate the Monte Carlo results and is shown to improve on the other methods. In Part B a self-consistent mean field theory for molecular polarizability is used, together with the RHNC approximation used in Part A, for a polarizable dipole-linear quadrupole fluid with ammonia-like parameters. The dielectric constant is calculated at three sub-critical temperatures and it is found to be quite sensitive to the quadrupole moment. Experimental results for ∈ are shown to be well within the uncertainty, set by the quadrupole moment, in the calculated ∈ values. These calculated ∈ values are shown to be significantly larger than the dielectric constants for the equivalent non-polarizable system.Science, Faculty ofChemistry, Department ofGraduat

A theoretical study of ammonia-salt mixtures in bulk solutions and interfacial regions

Five models, ranging from a full molecular polar/polarizable model with C₃v symmetry, to the primitive model of ions in a dielectric continuum, have been used to study the properties of ammonia both as a pure liquid and as a solvent. Ammonia is modelled as a multipolar polaxizable hard sphere and ions as charged hard spheres. Using these models, in conduction with the Reference Hypernetted-chain integral equation theory, ammonia has been studied as a pure liquid, as a solvent near charged and uncharged surfaces, and in electrolyte solutions of finite concentration. The formalism of Kirkwood and Buff was used to obtain thermodynamic quantities of ionic solutions from calculated distribution functions. Structural, thermodynamic and. dielectric properties were calculated for pure ammonia and were compared with experiments where possible. Values for the dielectric constant and the configurational energy were found to compare favorably with experiment. Ammonia formed a relatively dense, highly structured layer within two solvent diameters of an uncharged surface. This structure was analyzed in terms of angular probability distributions of the molecular dipole vector and the NH-bond direction, and was found to be similar to that of frozen ammonia. The extreme asymmetry of solvation of unlike charges in ammonia was also investigated. Small cations were found to be more favorably solvated than small anions, but as the ion size was increased, the situation reversed. Estimates of the number of ion pairs in liquid ammonia and their effects on the behavior of mean molar activity coefficients were examined. Large differences between experimental activity coefficients and the Debye-Hückel hmiting law could not be explained by the usual ideas of ion pairing. It was found that the integral equation theories appear to have no solution between ionic concentrations of about 2 x 10⁻⁴M and 2 x 10⁻²M for either molecular or continuum models. Using rigorous stability criteria, this behavior was shown to be consistent with the onset of a phase change. It is proposed that such phase separation phenomena might explain the unusual behavior of the experimental activity coefficients.Science, Faculty ofChemistry, Department ofGraduat

An analytical study of Elliott Carter's piano sonata

This analytical study of Elliott Carter's Piano Sonata focuses on middleground structural aspects found in the work such as phrases, phrase groupings, cadences and note collections. These are examined under four main headings: The Articulation of Phrases looks at the division of large passages into phrases, showing the various ways in which new phrases are marked. These include sudden changes in texture and register, restatements of thematic material, and recurring characteristics that appear at important cadential points. The Unification of Extended Passages by Middleground Stepwise Motion focuses on the rising linear motion that connects the individual phrases of many of these larger passages. Correlations between thematic material and phrase contours are also explored. The Relationship of Vertical Intervals and Note Collections to the Character and Phrase Rhythm of Particular Passages further examines phrase articulation by means of changes in note collections, with distinctions among phrases arising from the correlation of consonant vertical intervals with passages of linear motion and dissonant vertical intervals with passages that are more static. Anticipation and Overlapping of Materials describes an important aspect of the Sonata's overall structure in which themes and motives, as well as characteristic intervals of these materials are used to link the two movements of the work by a network of anticipations and flashbacks. An examination of the final climactic Maestoso section of the first movement (mm. 252-264) provides a summary of the various compositional aspects described in this study.Arts, Faculty ofMusic, School ofGraduat