Using attosecond pulses to reveal new information about the photoelectric effect

Scientists from the Stanford National Accelerator (SLAC) laboratory of the US Department of Energy have revealed new information about the photoelectric effect using attosecond pulses: the delay time of photoelectric emission is as long as 700 attosecond, far exceeding previous expectations. The latest research challenges existing theoretical models and helps to reveal the interactions between electrons more deeply, promoting the development of technologies such as semiconductors and solar cells. The relevant paper titled 'Attested delays in X-ray molecular ionization' was published in the latest issue of the journal Nature.

The photoelectric effect refers to the phenomenon in which photons interact with molecules or atoms on a metal surface when light is irradiated, causing the metal surface to release electrons. This effect laid the theoretical foundation for quantum mechanics, but the so-called photoelectric emission delay time has always been a fiercely debated topic. The latest progress in the field of attosecond science provides an important tool for further revealing the secret of this time delay.

Research schematic diagram
In the latest study, researchers used attosecond (10 billionth of a second) X-ray pulses emitted by SLAC's linear accelerator coherent light source to ionize core level electrons and "kick" them out of molecules. Then, they used separate laser pulses to "kick" the electrons in slightly different directions based on their emission time to measure the delay time of photoelectric emission.

Research shows that this delay time is as long as 700 attosecond, and the interaction between electrons plays an important role in this delay. Researchers point out that measuring and interpreting these time delays can help better analyze experimental results, especially in fields such as protein crystallography and medical imaging where the interaction between X-rays and matter is crucial. They plan to delve deeper into the electronic dynamics within different molecular systems, further revealing new information on electronic behavior and molecular structure.

Source: Science and Technology Daily, Author: Liu Xia