Azobenzene is one of the best-known molecules that can be switched between two forms by light. However, the question of how the molecule moves in the first few picoseconds (trillionths of a second) after it absorbs light has remained unresolved for nearly 50 years.

TRXL experiments were conducted at the XSS beamline of the Pohang Accelerator Laboratory X-ray free-electron laser (PAL-XFEL) facility. Key experimental parameters are summarized in Supplementary Table 1. A laser-pump and X-ray-probe scheme was used to initiate the photoisomerization reaction of azobenzene. Optical laser pulses at a wavelength of 400 nm, generated as the second harmonic of a femtosecond titanium:sapphire laser system, were used as the pump pulses. These pump pulses with an energy of 8.5 µJ were focused onto the sample with a spot size of 55 × 66 µm2 (full-width at half-maximum (FWHM), horizontal × vertical), corresponding to a laser fluence of 1.5 mJ mm−2. The repetition rate of the optical laser was 30 Hz. The X-ray beam, used as the probe, was focused onto the sample with a spot size of 20 µm × 20 µm (FWHM), delivering approximately 1 × 1012 photons per pulse at a repetition rate of 60 Hz, with a centre energy of 15.01 keV. By utilizing the X-ray with twice the repetition rate of the laser, we alternately measured laser-on and laser-off scattering images. The optical laser and X-ray beams were overlapped at a 10° crossing angle at the sample position. The temporal...

Reversible photocontrol of enzymes can be achieved with the azobenzene-based photoswitchable unnatural amino acid AzoF. Screening of 85 AzoF incorporation positions in tryptophan synthase identified ...

Generally semiconductor devices like transistors have fixed properties, but using an azobenzene (Azo) compound it’s possible to optically alter these properties by exposing them to UV light. This is demonstrated …read more

Generally semiconductor devices like transistors have fixed properties, but using an azobenzene (Azo) compound it’s possible to optically alter these properties by exposing them to UV light. This is demonstrated …read more

Generally semiconductor devices like transistors have fixed properties, but using an azobenzene (Azo) compound it’s possible to optically alter these properties by exposing them to UV light. This is demonstrated …read more

AbstractThe rich chemistry of molecular framework materials enables precise control of physico-chemical properties through structural design of framework t