An Off-lattice Model for Br Electrodeposition on Au(100): from DFT to Experiment

Since Br adsorption on Au(100) displays an incommensurate ordered phase, a lattice-gas treatment of the adlayer configurations is not reliable. We therefore use density functional theory slab calculations to determine the parameters necessary for the construction of an off-lattice model. We compute and analyze the total energy and electron density as the lateral Br position and coverage are varied. This allows the calculation of the corrugation potential, the short-range lateral interactions, the dipole moment (long-range interactions), and the residence charge. From these parameters, we construct an off-lattice model with no freely adjustable parameters. The simulation results compare remarkably well with experimental results.Comment: 42 pages, 15 embedded figures, submitted to Surface Scienc

Field-dependent chemisorption of carbon monoxide and nitric oxide on platinum-group (111) surfaces: Quantum chemical calculations compared with infrared spectroscopy at electrochemical and vacuum-based interfaces

Density Functional Theory (DFT) is utilized to compute field- dependent binding energies and intramolecular vibrational frequencies for carbon monoxide and nitric oxide chemisorbed on five hexagonal Pt-group metal surfaces, Pt, Ir, Pd, Rh, and Ru. The results are compared with corresponding binding geometries and vibrational frequencies obtained chiefly from infrared spectroscopy in electrochemical and ultrahigh vacuum environments in order to elucidate the broad-based quantum- chemical factors responsible for the observed metal- and potential-dependent surface bonding in these benchmark diatomic chemisorbate systems. The surfaces are modeled chiefly as 13- atom metal clusters in a variable external field, enabling examination of potential-dependent CO and NO bonding at low coverages in atop and threefold-hollow geometries. The calculated trends in the CO binding-site preferences are in accordance with spectral data: Pt and Rh switch from atop to multifold coordination at negative fields, whereas Ir and Ru exhibit uniformly atop, and Pd hollow-site binding, throughout the experimentally accessible interfacial fields. These trends are analyzed with reference to metal d-band parameters by decomposing the field-dependent DFT binding energies into steric (electrostatic plus Pauli) repulsion, and donation and back-donation orbital components. The increasing tendency towards multifold CO coordination seen at more negative fields is due primarily to enhanced back-donation. The decreasing propensity for atop vs multifold CO binding seen in moving from the lower-left to the upper-right Periodic corner of the Pt- group elements is due to the combined effects of weaker donation, stronger back-donation, and weaker steric repulsion. The uniformly hollow-site binding seen for NO arises from markedly stronger back-donation and weaker donation than for CO. The metal-dependent zero-field DFT vibrational frequencies are in uniformly good agreement with experiment; a semiquantitative concordance is found between the DFT and experimental frequency-field ("Stark-tuning") slopes. Decomposition of the DFT bond frequencies shows that the redshifts observed upon chemisorption are due to donation as well as back-donation interactions; the metal-dependent trends, however, are due to a combination of several factors. While the observed positive Stark-tuning slopes are due predominantly to field-dependent back-donation, their observed sensitivity to the binding site and metal again reflect the interplay of several interaction components. (C) 2000 American Institute of Physics. [S0021-9606(00)70234-0

The Impact of Integrated Student Experiences on Learning

In a cluster of courses called Food for Thought, seven faculty from different departments (including Biology, Economics, Sociology, Chemistry, Health and Wellness, and Foreign Language) teach students about food information, food consumerism, nutrition and health. The classes all have a shared learning outcome focused on developing the student as an informed consumer of food.  Each semester, faculty teach a food-related course from their respective disciplinary perspective while also incorporating cross-course interactions that allow for both integration of disciplinary knowledge and student-to-student learning opportunities. Previous research demonstrated that this approach leads to student perceptions of learning gains (Authors, 2011). Building on that work, this research directly assesses student learning in the Food for Thought cluster. The results demonstrate that exposure to multiple disciplines covering a shared topic enhances learning through greater student ability to integrate diverse forms of knowledge and to see an issue from multiple perspectives. These findings demonstrate the value of multidisciplinary learning opportunities for students

Prosecutors and Use of Restorative Justice in Courts: Greek Case

The purpose of this research study was to examine the experiences of prosecutors in Athens, Greece, as they implement a restorative justice (RJ; mediation) model in cases of intimate partner violence (IPV). Greece recently enacted a new legislation related to domestic violence, part of the requirement is mediation. This study used semi-structured interviews with 15 public prosecutors at the courts of first instance and three interviews with facilitators of mediation process. The findings indicate widespread role confusion. Prosecutors’ experiences, professional positions, and views of RJ in adult cases of gendered violence were shaped by their legal training. That is, their perceptions reflected their work in an adversarial system. Their views were complex yet ultimately unreceptive and their practices failed the victims of IPV. The study report concluded with recommendations for the legislators and for better preparation of court actors. </jats:p