physics

Hans Frauenfelder

Hans Frauenfelder 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 Hans Frauenfelder rather than just read about it. In short: Hans Frauenfelder (July 28, 1922 – July 10, 2022) was an American physicist and biophysicist notable for his discovery of perturbed angular correlation (PAC) in 1951. In the modern day, PAC spectroscopy is widely used in the study of condensed matter physics.

Key takeaways

Hans Frauenfelder belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hans Frauenfelder to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hans Frauenfelder from memory before moving on to harder problems.

Reference excerpt

Hans Frauenfelder (July 28, 1922 – July 10, 2022) was an American physicist and biophysicist notable for his discovery of perturbed angular correlation (PAC) in 1951. In the modern day, PAC spectroscopy is widely used in the study of condensed matter physics. Within biophysics, he is known for his experimental and theoretical research on the dynamical behavior of protein tertiary structure.

Education Frauenfelder received his Dr. sc. nat. in physics in 1950 at the Swiss Federal Institute of Technology (ETH) in Zurich under Paul Scherrer, his thesis being on the study of radioactive surfaces. At ETH, he was also taught by Gregor Wentzel and Wolfgang Pauli. Through Pauli, he also got to know many of the leading scientists such as Hendrik Kramers, Werner Heisenberg, Hans Jensen, and Wolfgang Paul.

Career Frauenfelder migrated to the United States in 1952, joining the department of physics at the University of Illinois at Urbana-Champaign as a research associate. He stayed at the UIUC till 1992, ultimately as Center for Advanced Study Professor of Physics, Chemistry, and Biophysics. His research interests included nuclear physics, particle physics, conservation laws, the Mössbauer effect, and the biophysics of protein folding and motions. Frauenfelder was a visiting scientist at the European Organization for Nuclear Research (CERN) in 1958/59, 1963 and 1973. In 1992, Frauenfelder moved to the Los Alamos National Laboratory where he directed the Center for Nonlinear Studies (CNLS) until 1997. In 1997, he left CNLS and joined the theoretical biology and biophysics group at Los Alamos (T-10 recently renamed T-6) and continued research in biophysics. Frauenfelder was the inventor of the "Frauenfelder Rules", which provide a guideline about the most successful way to run a seminar at a research workshop, according to which a presentation should take up no more than 66% of the allotted time, the rest being used for questions and in-depth discussion.

Personal life Frauenfelder died in Tesuque, New Mexico, on July 10, 2022, eighteen days away from his 100th birthday.

Honors Frauenfelder was elected a Fellow of the American Physical society in 1961. He was a member of the National Academy of Sciences (elected in 1975), the American Philosophical Society, and a Foreign Member of the Royal Swedish Academy of Sciences.

Publications Thomas G. Ebrey, Hans Frauenfelder, Barry Honig, and Koji Nakanishi Biophysical Studies, University of Illinois Press (1988) ISBN 0-252-01528-2 Hans Frauenfelder, The Mössbauer Effect, W. A. Benjamin, Inc. (1962) ASIN B000Q7QEBG Hans Frauenfelder and Ernest M. Henley, Subatomic Physics, Benjamin Cummings (1991) ISBN 0-13-859430-9

See also Wolfgang Pauli Paul Scherrer Quantum Aspects of Life

References

External links References on Perturbed Angular Correlation (PAC) PAC Spectroscopy Frauenfelder's homepage Frauenfelder's math genealogy

Illustrations

Worked examples

Example 1 — a first encounter with Hans Frauenfelder

Start with the simplest possible case. Write down what Hans Frauenfelder 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 Hans Frauenfelder 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 Hans Frauenfelder 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 Hans Frauenfelder

In research: Hans Frauenfelder 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 Hans Frauenfelder 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: Hans Frauenfelder is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1922 births, 2022 deaths, 21st-century American physicists, so understanding it makes those chapters shorter.
In everyday life: Look for Hans Frauenfelder 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 Hans Frauenfelder in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hans Frauenfelder 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 Hans Frauenfelder out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hans Frauenfelder in simple terms?

Why does Hans Frauenfelder 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 Hans Frauenfelder?

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 Hans Frauenfelder.