电磁场是一种由带电粒子产生的物理场，它会影响带电物体在其中的行为，因此我 们可以认为电磁场中的原子和分子是一种新的物质状态。在整个空间中，电磁场无限延 伸并且描述了电磁之间的相互作用，它提供了一种对物质特性操作的新方法，例如色 散，吸收以及各种非线性特性等等。运用电磁场可以改善材料的性能，例如纳米结构或 光子晶体材料的制造，甚至可以超出一些天然材料自身特有的限制。 在上个世纪，前苏联科学家Veselago提出了有关负折射率的概念。负折射率材料是一 种人造光学结构，其折射率对于特定频率范围内的电磁波是负的，因此电磁波可以在相 反的方向上传播，这使得衍射极限下分辨成像成为可能。负折射率材料具有不寻常的光 学特性，如理想成像等等，这种性质使得制备负折射率材料成为研究热潮。 理论上已经证明M¨obius分子中存在负折射。然而，分子产生负折射所需的条件是十 分严格的。在本文中，我们找到了一种拓宽M¨obius分子负折射带宽的新方法。通过线性 响应理论，我们利用电偶极跃迁和磁偶极跃迁的相干耦合，诱导M¨obius分子手性，产生 负折射。这种利用电磁场交叉耦合诱导分子手性的方法可以扩大负折射率产生的频率区 间，使得M¨obius分子发生负折射的条件不再那么苛刻。扩大负折射率的频率区间使得做 出的负折射率材料具有大规模应用范围，并有望替代透镜成为更好的光学观测工具。

Electromagnetic field is a kind of physical field generated by charged particles, which affects the behavior of charged objects. Therefore, we can think that atoms and molecules in electro- magnetic fields are a new state of matter. Throughout the space, the electromagnetic field extends infinitely and describes the interaction between the electromagnetics, which provides a new way of operating on the properties of matter, such as dispersion, absorption, and various nonlinear properties. The use of electromagnetic fields can improve the properties of materials, such as the fabrication of nanostructures or photonic crystal materials, and can even exceed the limitations of some natural materials. In the last century, former Soviet scientist Veselago proposed the concept of negative refrac- tive index. The negative refractive index material is an artificial optical structure whose refractive index is negative for electromagnetic waves in a specific frequency range,which makes it possible to distinguish imaging at the diffraction limit. Negative refractive index materials have unusual optical properties, such as ideal imaging, etc. which makes the preparation of negative refractive index materials a research boom. Theoretically, it has been proved that there is negative refraction in the M¨obius molecule. However, the conditions required for the molecule to produce negative refraction are very strict. In this paper, we have found a new way which proof M¨obius molecule have negative refraction. Through linear response theory, we use the coherent coupling of electric dipole transition and mag- netic dipole transition to induce M¨obius molecular chirality and generate negative refraction. This method of using molecular electromagnetic cross-coupling to induce molecular chirality enriches the way to obtain negative refraction and makes the condition of negative refraction of M¨obius molecules less severe. The negative refractive index materials we hope to make have a large-scale application range and are expected to replace lenses as better optical observation tools.