Technique to make ultrafast movies of chemical reactions
doi:10.1038/nindia.2018.49 Published online 30 April 2018
Physicists have developed a technique that employs extremely tiny light pulses to track and record electron movement in ultrafast processes such as chemical reactions – a significant step towards unveiling the secrets of ultrafast natural processes such as photosynthesis1.
Extremely tiny light pulses are used to study electron movement in atoms, molecules and transparent solids. However, it is difficult to gain insights into complex molecular systems.
Scientists from the Indian Institute of Technology Bombay, in Mumbai, India, led by Gopal Dixit, created ultra-small light pulses of extreme ultraviolet light and shone it on to a target of a known material. Each pulse lasts for an attosecond, which equals to a millionth of a trillionth of a second.
The incidence of a first light pulse ionised the target, making it emit a photoelectron. A second light pulse then tracked and recorded the electron emission and light-induced ionisation.
The light pulses, lasting for attoseconds, can play the role of a camera by recording fast-happening chemical transformations in natural processes such as vision and photosynthesis. This can help make ultrafast movies of such natural processes.
Each of life’s molecular building blocks, such as sugars and amino acids, has a twin – not an identical one, but a mirror image. In other words, there are both left- and right-handed amino acids and sugars in nature. The attosecond light pulses can be very useful for identifying such handedness of biological molecules such as DNA and carbohydrates, says lead researcher Dixit.
1. Jiménez-Galán, A. et al. Attosecond recorder of the polarization state of light. Nature. Communications. 9, 850 (2018)