#single-molecule spectroscopy
Every note tagged #single-molecule spectroscopy, newest first — or browse the full archive.
One dye, one transition: how DCDHF-Me2 earns the two-level picture
The blinking-to-absorption note modeled a fluorescent dye as two levels and named what that hides. Computing the actual excited-state manifold of DCDHF-Me2 — a push-pull dye engineered for single-molecule imaging — gives a sharper answer than we planned. Its visible absorption is essentially one transition, and the rest of the manifold lives in the deep UV; benzene, the dye's own parent ring, shows the opposite arrangement for a reason symmetry makes plain.
From blinking to absorption: how one molecule becomes a spectrum
A single fluorescent molecule blinks; a cuvette full of the same molecules gives a smooth absorption band. The two pictures are the same Jablonski diagram read at different scales — one molecule versus an ensemble, one photon at a time versus a steady-state rate. This post traces the path from quantized absorption and emission events to a bulk spectrum, and extends the same diagram to two-photon absorption as the nonlinear version of the same transition.