Permittivity and permeability of pentagon configuration molecules with different symmetry breaking and their applications

Abstract

Some kinds of psychoactive drugs have the structures which are called split-ring resonators (SRRs). SRRs might result in negative permittivity and permeability simultaneously in electromagnetic field. Simultaneous negative indexes can lead to the famous phenomenon of negative refraction. This optical property makes it possible to distinguish synthetic cannabinoids from other abusive psychoactive drugs in the UV-vis region. This optical method is non-damaged and superior in forensic science. In this paper, we use tight-binding model calculating the permittivity and permeability of the main ingredients of synthetic cannabinoids. At the same time, we give two more results of zolpidem and caffeine. Further we discuss the negative refraction of the category of zepam qualitatively.In 1968, Veselago originally introduced the concept of negative index material (NIM) which exhibit unusual optical property. 1 For this kind of material, the permittivity and permeability can be negative simultaneously in electromagnetic field, which might bring about the phenomenon of negative refraction. Pendry et al.2-6 developed Veselago's theory, their research pointed out that the configuration of split-ring resonators (SRRs) 3 which had non-trivial symmetry breaking 7 is an effective way to realize negative refraction. Negative refraction has became more and more popular these decades, new researches and applications come to practice. For instance, the perfect lenses which are made by NIM can focus all Fourier components of image, both their propagating and evanescent waves are amplified, the quality of image and the detection sensitivity are improved. [8][9][10][11][12] After the theoretical derivation, Shelby et al. 13 gave the experimental realization two years later. According to Veselago's theory, molecules with SRRs configurations such as extended metal atom chains (EMACs), have led a fresh direction of physical and chemical research. 14-37 Recently many fabulous works in different fields come forth, such as invisible cloaking, 38-43 liquid crystal magnetic control, 44 anapole moment, 45 detection of latent fingermarks, 46-48 etc. Inspired by these ideas, negative refraction plays more and more important role in forensic science field since it is a non-damaged optical method to test materials. More importantly, a small categories of molecules could show negative respondence to eletromagnetic fields. 49 Utilizing this property, these categories of molecules can be distinguished from others. This is significant to differentiate psychoactive drugs in forensic science. As a matter of fact, according to the theoretical derivation and calculation, we point out that the main ingredients of synthetic cannabinoids, the category of zepam, zolpidem and caffeine show various degree of negative refraction while other psychoactive drugs can not. We discuss the result of synthetic cannabinoids, zolpidem and caffeine quantitatively and the category of zepam qualitatively. This paper is organized as following: In section II, we previousl...