Modifications are presented for the iodine clock reaction to introduce the concept of activity and to help students better appreciate molecular aspects of chemical equilibrium. The addition of an unreactive salt affects the activity of the reactants in the iodine clock reaction. The difference in activity affects how long the iodine clock reaction…

As a widely applied theory that has found success across many fields, density functional theory (DFT) is largely taught. Typically, the most effective way to convey DFT concepts is through illustrative examples that are currently lacking in available resources. In this work, we demonstrate total energy calculations for H[subscript 2] using…

Auxiliary Tanabe-Sugano diagrams are presented. They enable a rapid and reliable graphical derivation of Dq/B and C/B crystal field parameter ratios from spectroscopic data. Using these values, one can calculate Dq and B by employing the original Tanabe-Sugano diagrams. Subsequently, C can also be calculated irrespective of the value C/B fixed in…

Benzoin, an [alpha]-hydroxy ketone, is stereoselectively reduced by sodium borohydride to yield hydrobenzoin, the stereochemistry of which is determined by acetalization and analysis of the derivative by NMR spectroscopy. This classical experiment has been enhanced by modern spectroscopic and computational analysis to enable students to…

For solid solutions with the same arrangement of atoms, the size of a unit cell depends on the size of the atoms in the unit cell. The distance between nuclei also helps determine how strongly electrons are held, which changes the band gap energy. Samples of semiconductor CH[subscript 3]NH[subscript3]Pb(I[subscript…

The concepts taught in an undergraduate physical chemistry course are directly related to the molecular processes governing climate change, yet the connections between quantum mechanical molecular properties and global warming are rarely made explicit. To improve student knowledge about climate change, we developed a three-part activity that…

In this article, we describe a fully computational laboratory exercise that results in an increase of students' understanding of what quantum chemical geometry optimization calculations are doing to find minimum energy structures. This laboratory exercise was conducted several times over multiple years at a small private undergraduate institution,…

In this paper, we develop a general but very simple mathematical foundation for the predefined coefficient graphical method of Hückel molecular orbital theory (HMO). We first present the general solution for the recurrence relation of the coefficients of Hückel molecular orbitals (MOs). Subsequently, for all the three unbranched hydrocarbons,…

The point particle is an idealized object where rotational and vibrational motion is ignored. Nevertheless, in many cases such degrees of freedom play a significant role. For example, the rotation and vibration of a molecule is an important "reservoir" of its internal energy. The excitation of these types of motion can occur during the…

Recent progress in elucidating chemical reactions allows to explain chemistry by the potential energy of the involved chemical structures. Nevertheless, from an educational point of view, empirical results indicate that students often do not connect the core idea of energy with other chemical concepts. From a resource-oriented perspective,…

In multielectron atoms or molecules, quantized electronic energy states known as term states provide a framework for interpreting absorption and emission spectra. Enumerating the term states associated with any particular electron configuration is possible using time-honored procedures, but the underpinnings of the methods do not always receive…

Molecules and Computer: Chemistry Calculations in Class (MC[superscript 4]) is a computational laboratory intended for final-year high school or undergraduate students. The topic is the antioxidant potential of anthocyanidins, which is chemically related to their radical scavenging action via the mechanism of hydrogen atom transfer (HAT). This…

The contemporary Human activity utilizes huge volumes of digital data to solve efficiently multiple socio-economic, scientific and technical problems. Now the big data analysis is mainly oriented to the socioeconomic sphere with a goal to lift the profit. The science and technology to penetrate deeper in the nature of objects and systems under…

This is a fundamental and pedagogical work in quantum physics/chemistry, where we try to illustrate the Mulliken's question, "What are the electrons really doing in molecules?". And we also briefly review the development of the most popular numerical approaches in computational chemistry. We examine in a novel approach, how we can…

Nitrogen gas dominates the Earth's atmosphere but is largely ignored. Molecular nitrogen is extremely stable and so nitrogen is termed inert. What would happen if another 'inert' gas were the dominant species instead of molecular nitrogen? Here we show how unique nitrogen is and how important it has been to life on planet Earth.