Abstract
Racemic solid films of DL-isovaline were irradiated with circularly polarized light from free electron laser. Circular dichroism spectra of the films after the irradiation showed new Cotton peaks. The signs of the peaks were completely reversed depending on the helicity sign for the circular polarization (left- or right-handed) and, therefore symmetric circular dichroism spectra were obtained. Absorption spectra of the films after irradiation slightly shifted to low-energy direction but the absorption peak profile was hardly changed. The new Cotton peak appearance is due to not simple asymmetric photolysis of the molecule but to chirality emergence caused by construction distortion accompanied with conformation change of the molecule. These results show that abiotic synthesized organic molecules in racemic body on interstellar materials may emerge chirality, whose asymmetric direction is according to the helicity of the circularly polarized light exposed in space.
