Residual dipolar couplings (RDCs) and residual anisotropic chemical shifts (RACSs) are produced by the partial alignment of solution NMR samples. RDCs and RACSs yield high-resolution structural and dynamic information on the orientation of bonds and chemical groups in molecules. Many molecules form oligomers or have intrinsic symmetries, which may simplify the analysis of their partial alignment datasets. In this report, we explore the theory of partial alignment using an irreducible spherical representation, and we investigate the impact of molecular symmetry on the alignment of molecules. Though previous studies have reported simplified relationships on the partial alignment of molecules bearing different symmetry groups, we show that these simplified relationships may not be universal and only apply to a limited set of systems.

残留的偶极偶合（RDC）和残留的各向异性化学位移（RACS）是通过溶液NMR样品的部分比对产生的。RDC和RACS产生有关分子中键和化学基团取向的高分辨率结构和动态信息。许多分子形成低聚物或具有固有对称性，这可能简化其部分比对数据集的分析。在本报告中，我们探索了使用不可约球形表示的部分比对的理论，并研究了分子对称性对分子比对的影响。尽管先前的研究已经报告了带有不同对称基团的分子的部分排列的简化关系，但我们表明这些简化关系可能并不通用，仅适用于一组有限的系统。