应用了电子自旋共振技术来研究有机半导体1，1 -二苯基-2-三硝基苯肼( DPPH) 中自由基未成对电子的超精细结构和塞曼劈裂.通过测量共振磁场大小和微波频率，我们得到了自由基未成对电子的朗德g 因子.在实验中，一种混合接头 ( magic-T) 波导管被用来提高信噪比.朗德g 因子的测量结果为2.033±0.0003，与其他实验中测得的期望值2.0036 相吻合.这 方法可以用以研究各种材料、生物系统中自由基未成对电子，并可进一步应用于研究电子芯片微电感上的自由基.

We use electron spin resonance ( ESR) to study the properties of the unpaired electron in an organic chemical compound 2，2 -diphenyl-1-picrylhydrazyl ( DPPH) ，including its hyperfine coupling with the nucleus and its Zeeman splitting under magnetic field. The Lande-g factor is obtained by measuring the resonance magnetic field and microwave frequency. A magic-T waveguide is applied to increase the signal-to-noise ratio. The Lande-g factor is measured to be 2.033±0.0003，which agrees well with the expectation reference value 2.0036 found in other experiments. This method can be used to study the unpaired electrons in various materials and biosystems. And it also provides a promising method to study the radicals of micro-inductors on chips.