In order to observe the rotation of molecules, it is necessary to take pictures on a very fine time scale.This is not enough to shoot 1 million frames per second, which is possible with a commercially available high-speed camera.The problem of the number of frames has already been cleared by irradiating a laser that can irradiate 2 trillion times per second.However, it was still necessary to clear two issues in order to observe the rotation of the molecule.

One is that it is not possible to follow the movement of each and every molecule that rotates at high speed and minute.The other was that the molecule had to be in a dilute gaseous state. The first task was to find out that the direction of rotation can be aligned by irradiating two lasers in a row for a very short time.Another challenge could be solved by continuously irradiating the third powerful laser.Molecules exposed to a powerful laser emit multiple electrons from the inside.At this time, the atoms that made up the molecule explode and scatter into pieces.Since the direction of flight coincides with the orientation of the molecule immediately before the explosion, it is possible to investigate the distribution of the orientation of the molecule by detecting the debris.By creating a state in which the molecules are aligned and rotating in this way, bursting them one by one to make them into a gas state, and examining them, we succeeded in capturing the rotation of the molecules as a moving image.

　In this way, it became possible to visually understand the essence of molecular motion.Measuring the motion of a molecule is also the basis for taking advantage of the properties of a molecule.For example, the rotation of these molecules in these studies could be used as a stopwatch alternative when measuring phenomena on a very short time scale.
　
Source:[Tokyo Institute of Technology] Succeeded in high-resolution video recording of the rotational motion of molecules reaching 1 billion times per second