Search

Understandings of the nature of scientific inquiry (NOSI), as opposed to engaging students in inquiry learning experiences, are included in science education reform documents around the world. However, little is known about what students have learned about NOSI during their pre-college school years. The purpose of this large-scale follow-up international project (i.e. 32 countries and regions, spanning six continents and including 3917 students for the high school sample) was to collect data on what exiting high school students have learned about NOSI. Additionally, the study investigated changes in 12th grade students' NOSI understandings compared to seventh grade (i.e. 20 countries and regions) students' understandings from a prior investigation [Lederman et al. (2019). An international collaborative investigation of beginning seventh grade students' understandings of scientific inquiry: Establishing a baseline. "Journal of Research in Science Teaching," 56(4), 486-515. https://doi.org/10.1002/tea.21512]. This study documents and discusses graduating high school students' understandings and compares their understandings to seventh grade students' understandings of the same aspects of scientific inquiry for each country. It is important to note that collecting data from each of the 130+ countries globally was not feasible. Similarly, it was not possible to collect data from every region of each country. A concerted effort was made, however, to provide a relatively representative picture of each country and the world.

Photoelectrochemistry is used to study the effect of molecular chirality and charge transfer on the thiol-terminated, self-assembled chiral scaffold monolayers containing a porphyrin chromophore. The results show that a symmetry constraint on the electronic coupling between the porphyrin and scaffold can be a useful mechanism for the photocurrent asymmetry.

The electronic properties of hybrid inorganic/organic thin films are investigated where the inorganic components are monodisperse CdS quantum size particles and the electronic properties of hybrid Langmuir-Blodgett films are studied. In this case, low-energy photoelectron spectroscopy is applied in which the energy of photoelectrons, ejected from the metal substrate or films themselves is measured.

The direct observation of collective electronic properties in assembled CdS quantum particles (QPs) arranged in periodic layers in reported. The attenuated low energy photoelectron spectroscopy (A-LEPS) method is used to study the electronic properties of the QPs and the results indicate that A-LEPS method provides information about the populated electronic states of the QPs, and also provides a clear signature for the interactions between CdS QPs in the film.

Our understanding of processes involved in two-photon photoemission (2PPE) from surfaces can be tested when we try to exercise control over the electron emission. In the past, coherently controlled 2PPE has been demonstrated using very short pulses and single crystal surfaces. Here we show that by applying polarization pulse shaping on surfaces, it is possible to vary both the angular distribution of the emitted photoelectrons and the total photoemission yield. The presented 2PPE experimental setup introduces pulse shaping in the visible range, which is a unique property that allows control of polarization. We relate the ability to use polarization as a means of control to the surface corrugation. [ABSTRACT FROM AUTHOR]

The effect of a self-assembled organized organic monolayer on the two-photon photoemission from semiconductor substrates was investigated. It has been found that the monolayer affects the relative yield of photoelectrons emitted by p-polarized versus s-polarized light. In addition, the monolayer affects the angular distribution of the ejected electrons. The effect on the photoelectron yield is attributed to the monolayer “smoothing” the electronic potential on the surface by eliminating surface states and dangling bonds. The effect on the angular distribution is attributed to a post-ejection interaction between the photoelectrons and the adsorbed molecules. [ABSTRACT FROM AUTHOR]

Unique occurrence of magnetism is shown, in which magnetism appears ex nihilo, when organic molecules are self-assembled as monolayers on gold substrate. The molecules as well as the substrate, when they stand alone, are diamagnetic. Using a superconducting quantum interference device type magnetometer we obtained direct evidence that close-packed organized thio-organic films adsorbed on gold substrates possess magnetic properties at room temperature. The films studied show very high specific magnetization, up to many tens Bohr magnetons per adsorbed molecule, with a very small hysteresis. It is highly anisotropic and shows almost no temperature dependence. The magnetism observed is related to charge transfer between the organic layer and the metal substrate. Yet, the uniqueness here is that many spins are polarized per adsorbed molecules. The magnetic effect is related to the two dimensional organization of the organic molecules on the metal substrate which might explain the high anisotropy. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The electronic properties of absorbed organic molecules are investigated by two-photon low-energy photoelectron transmission (LEPET) spectroscopy. Two photon LEPET is used to study the electronic structure of the absorbed layer, the nature of the electronic states and the interaction between the absorbates and the metal substrate.