原子核效应是由于原子核的有限质量和电磁结构与原子中电子的相互作用而对原子结构和光谱产生的影响，是一个既与原子物理又和原子核物理相关的交叉研究领域。如果原子物理理论能够提供精确的原子参数，结合高精密原子光谱测量，将可以提取原子核的相关参数，从而对研究原子核结构，尤其是放射性原子核性质的研究提供了必要的帮助。我们将在多组态Dirac-Hartree-Fock理论和活动空间方法的框架下，系统地研究复杂原子体系中的电子关联效应，发展计算复杂原子体系原子参数的高精密方法。同时，我们将研究相对论效应对复杂原子体系质量偏移的影响，发展在全相对论框架下计算复杂原子质量偏移的方法。在超精细结构方面，我们将发展一套程序考虑原子核核磁化分布效应对于磁偶极超精细结构的影响。最后，我们将应用发展的方法和程序到目前感兴趣的原子体系中，计算这些体系的超精细结构和同位素偏移，与实验结合确定原子核的相关性质。

The interactions between the nucleus with finite mass and electromagnetic structures and electrons in an atomic system give rise to effects on atomic structures and spectra, which are called as nuclear effects in atoms. Studies on nuclear effects in atoms, therefore, build a bridge between nuclear physics and atomic physics. If accurate atomic parameters are available, combining with high-precision measurements on atomic spectra, one is able to extract nuclear parameters such as nuclear root-mean-square radii or nuclear quadurpole moments. This is a considerably useful method to study nuclear properties, especially for radioactive nucleus. In the framework of the multi-configuration Dirac-Hartree-Fock theory and the active space method, we plan to systematically investigate electron correlation effects in complex atomic systems, and to develop a method to accurately and efficiently calculate atomic parameters. In addition, we will investigate relativistic effects in mass shifts of complex atomic systems, develop a fully relativistic method to compute mass shifts. About hyperfine structures, we will make a program so as to take into account the effect of nuclear magnetization on magnetic dipole hyperfine structures. Based on these studies, we will also perform a few calculations on hyperfine structures and isotope shifts in atoms that are interesting with respect to nuclear physics. These calculations will be also helpful for investigate the relevant nuclear properties in the near future.