Biophysical Spectroscopy Atlas
Thirty-two techniques arranged by the physical process they exploit, each with its governing equations, what it reveals about biomolecules, and where it stops working. Select any technique, on the map or on the spectrum, to open its full card. Four live calculators and a question-to-method guide close the page.
- Physical process: absorption, emission, scattering, resonance, time-resolved, and nonlinear
- Transition or observable: electronic, vibrational, spin, polarization, correlation
- Technique: CD, FTIR, FRET, NMR, DEER, SAXS and others
- Variants and methods: pulse sequences, labels, geometries and analysis inside each card
The hierarchy · levels 1 to 3 shown here, level 4 inside each card. Six process families, twenty-two observables, thirty-two techniques. The first split is physical: what happens to the photon (or particle) at the sample. The second split is what transition or observable is read out. Cross-links in each card connect techniques that share a transition, such as IR and Raman for vibrations.
Energy axis. Where each technique sits on the electromagnetic spectrum. Bars mark the energy of the transition being probed, not necessarily the photon used. Raman is plotted at vibrational energies although it uses visible lasers; neutron spectroscopy is plotted at its energy transfers. Mass, surface and force methods without a spectral axis are omitted.
Shared physics. Twelve results every technique rests on. Each technique card assumes these. They explain why selection rules exist, why NMR is insensitive, why fluorescence is fast and phosphorescence slow, and why so many methods end up measuring a correlation function.
Time axis. Which technique sees which motion. Grey bars are biomolecular processes; coloured bars are the time windows techniques resolve directly. A technique can report on faster motions only as averages, and on slower ones only as static snapshots or by triggering.
Live calculators. Four numbers you will compute again and again. Everything here runs in your browser. Defaults are realistic examples; change them to match your system.
Question first. Which method answers my question? Start from the biological question, then pick a first-choice technique and at least one orthogonal check. Agreement between methods based on different physics is the strongest evidence you can offer a reviewer.
Going deeper. Standard references.
