Structural characteristics of glycine aggregates grown under sub-Terahertz irradiation

Although crystal growth methods in which intramolecular bonds are induced by infrared irradiation have been investigated recently, there is very little reported on the use of electromagnetic waves to enhance growth rates. In this study, we have irradiated with 40 GHz sub-Terahertz waves during the solution growth of glycine and investigated the effect on crystal growth. Highly crystalline α-glycine grew with or without irradiation and aggregates were formed. The growth rate, however, was strongly affected by sub-Terahertz wave irradiation, with the growth rate from nucleation approximately doubling. Powder X-ray structure analysis showed that the unique diffraction peaks of glycine tended to partially shift to lower angles, with the (−110) plane and (011) plane spacing expanding by about 0.1 % and 0.15 %, respectively. The FTIR results in the terahertz region show a large absorption near 6 THz, suggesting that the structure contains water molecules.