physics

Stephen Turnham Pratt

Stephen Turnham Pratt is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Stephen Turnham Pratt rather than just read about it. In short: Stephen Turnham Pratt is a senior chemist and Argonne Distinguished Fellow (awarded 2019). He is the theme lead for CSE's Fundamental Interactions Theme and the group leader for the Gas-Phase Chemical Dynamics group.

Key takeaways

Stephen Turnham Pratt belongs to physics; place it in that map before memorising details.
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Connect Stephen Turnham Pratt to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Stephen Turnham Pratt from memory before moving on to harder problems.

Reference excerpt

Stephen Turnham Pratt is a senior chemist and Argonne Distinguished Fellow (awarded 2019). He is the theme lead for CSE's Fundamental Interactions Theme and the group leader for the Gas-Phase Chemical Dynamics group. From September 2022 until July 2023, he served as the Interim Division Director for Chemical Sciences and Engineering (CSE) Division.

Research Pratt's research focuses on photoionization and photodissociation dynamics to understand how energy flows among the internal degrees of freedom in highly energized molecules. His experimental research program involves using laboratory-based lasers for multiphoton excitation and pump-probe experiments, and in using synchrotron sources for single-photon photoabsorption and photoionization studies of small molecules.

Education and career Pratt received his BA in Chemistry from Bennington College, his MS, MPhil, and PhD in Chemistry from Yale University under the direction of William A. Chupka, and after graduation in 1982, he joined Argonne National Laboratory as a postdoctoral appointee working with Patricia A. Dehmer. He has published more than 150 journal articles, and in 1995 was named a Fellow in the American Physical Society. He was nominated by the Division of Atomic, Molecular & Optical Physics, for "fundamental contributions to molecular physics through imaginative and innovative studies that probe electron-nuclear coupling, and, in particular, for his elegant experiments on molecular photoionization, predissociation, autoionization, and excited-state reactions."

Representative publications Young, L.; Kanter, E. P.; Krässig, B.; Li, Y.; March, A. M.; Pratt, S. T.; Santra, R.; Southworth, S. H.; Rohringer, N.; Dimauro, L. F.; Doumy, G.; Roedig, C. A.; Berrah, N.; Fang, L.; Hoener, M.; Bucksbaum, P. H.; Cryan, J. P.; Ghimire, S.; Glownia, J. M.; Reis, D. A.; Bozek, J. D.; Bostedt, C.; Messerschmidt, M. (2010). "Femtosecond electronic response of atoms to ultra-intense X-rays". Nature. 466 (7302): 55–66. Bibcode:2010Natur.466...56Y. doi:10.1038/nature09177. PMID 20596013. S2CID 205221300. Hoener, M.; Fang, L.; Kornilov, O.; Gessner, O.; Pratt, S. T.; Gühr, M.; Kanter, E. P.; Blaga, C.; Bostedt, C.; Bozek, J. D.; Bucksbaum, P. H.; Buth, C.; Chen, M.; Coffee, R.; Cryan, J.; Dimauro, L.; Glownia, M.; Hosler, E.; Kukk, E.; Leone, S. R.; McFarland, B.; Messerschmidt, M.; Murphy, B.; Petrovic, V.; Rolles, D.; Berrah, N. (2010). "Ultraintense X-Ray Induced Ionization, Dissociation, and Frustrated Absorption in Molecular Nitrogen". Physical Review Letters. 104 (25) 253002. Bibcode:2010PhRvL.104y3002H. doi:10.1103/PhysRevLett.104.253002. hdl:1811/47976. PMID 20867372. S2CID 28190205. Dehmer, P. M.; Pratt, S. T. (1982). "Photoionization of Argon Clusters". Journal of Chemical Physics. 76 (2): 843–853. Bibcode:1982JChPh..76..843D. doi:10.1063/1.443056. "Electric-Field Effects in the Near-Threshold Photoionization Spectrum of Nitric Oxide". Journal of Chemical Physics. 98 (12): 9241–9250. 1993. doi:10.1063/1.46440. Taatjes, Craig A.; Osborn, David L.; Selby, Talitha M.; Meloni, Giovanni; Fan, Haiyan; Pratt, Stephen T. (2008). "Absolute photoionization cross-section of the methyl radical". Journal of Physical Chemistry A. 112 (39): 9336–9343. doi:10.1021/jp8022937. PMID 18572896.

See also List of fellows of the American Physical Society (1972–1997)

References

Worked examples

Example 1 — a first encounter with Stephen Turnham Pratt

Start with the simplest possible case. Write down what Stephen Turnham Pratt claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Stephen Turnham Pratt before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Stephen Turnham Pratt ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Stephen Turnham Pratt

In research: Stephen Turnham Pratt appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Stephen Turnham Pratt in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Stephen Turnham Pratt is common in secondary-school and first-year university syllabi. It links to neighbouring topics 21st-century American chemists, American physicists, Argonne National Laboratory people, so understanding it makes those chapters shorter.
In everyday life: Look for Stephen Turnham Pratt outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Stephen Turnham Pratt in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Stephen Turnham Pratt means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Stephen Turnham Pratt out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Stephen Turnham Pratt in simple terms?

Why does Stephen Turnham Pratt matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Stephen Turnham Pratt?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Stephen Turnham Pratt.