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Chemical Education: Software Abstracts for Volume V C, Number 2 How a Photon Is Created or Absorbed Giles Henderson Eastern Illinois University Charleston. IL 61920 Robert C. Rittenhouse Walla Walla College College Place, WA 99324
A series of framestaken from the animation of the 2p to i s transition in a hydrogen atom (Figure 7 of "How a Photon Is Created or Ab-
John C. Wright Jon L. Holmes University of Wiswnsin-Madison Madison, WI 53706
This paper is written in Microsoft Word for the Macintosh. Spreadsheets written in Microsoft Excel have been embedded in the Word document to display some of the figures (rigid rotor and harmonic oscillator). QuickTime movies are the basis for the animations of electronic transitions for the hydrogen atom. Word, Excel, and QuickTime are all required in order to read the paper. In addition to its pedagogical value relative to enhanced understanding of quantum transitions, this paper pioneers a format that we expect will become more common in the future, namely a n electronic document that makes use of the graphic and calculational abilitiesof computers to enable better understanding of a n otherwise arcane topic.
"How a Photon Is Created or Absorbed" is a n electronic version of a paper by the same title published i n this Journal in 1979 (1).Only minor revisions have been made in the text, but the electronic medium allows the authors to provide interactive graphics and animations that illustra t e the points being made much more effectively than could be done in the print medium. Quantum transitions are typically represented by vertical arrows connecting energy levels, and the emphasis is on the requirement that the energy ofthe photon equal the difference between the two energies represented by two horizontal lines. It is natural for students to wonder what actually happens when a photon is created or absorbed by such a transition, b u t such questions are seldom addressed. This paper provides a visually interesting and quite striking model of the mechanism of the process. I t does so by means of spreadsheet calculations and graphic displays of dynamic quantum trajectories for transitions involving a rigid rotor and a harmonic oscillator, and animations of the behavior of electron density in a hydrogen atom undergoing the allowed 2p to 1s transition and the forbidden 2s to 1s transition. These replace static figures that appeared in the original paper. Harmonic Osclllato~
Dynamic quantum trajectory probability surface plotted by Excel spreadsheet (Figure 5 from"How a Photon Is Created or Absorbed).
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Journal of Chemical Education
sorbed).
Inorganic Nomenclature David B. Shaw Madison Area Technical College Madison, WI 53704 "Inorganic Nomenclature "is a Hypercard stack that is a drill-and-practice exercise in naming and writing formulas for inorganic compounds, both ionic and covalent. The stack consists of multiple-choice questions where a name or formula is given and the correct formula or name is chosen from alist offive possible answers. Aseries of introductory screens explains that throughout the tutorial the keyboard is inactivated, the cursor is kept in the "browse" mode, and navigation is by means of mouse clicks only At the end of the introduction a student chooses whether to start with a name and give a formula, start with a formula and give a name, or receive a random selection of these two types of questions. If the student requests, for example, "Compound Name to Formula", a n exercise can be chosen from a list of 60 names. Clicking on the first name on the list, iron(II1) chlorate, generates a question that requests the formula. Five possible answers are provided on five separate lines labeled as choices A through E. When the student clicks on a choice, a bullet appears next to it. A n incorrect answer generates a message explaining a possible reason why the choice is incorrect. For iron(II1) chlorate, choosing "FeCIF a s the answer generates the message, "This compound does not contain a monatomic anion. Please use this information to make another choice." At any time the student can access help that includes a periodic table, a list of polyatomic ions employed in the tutorial, and nomenclature
