Data for: Test of the Validity of Bragg´s Rule for Mean Excitation Energies

We are investigated the effect of chemical binding on the validity of Bragg’s rule for the calculation of stopping cross sections and mean excitation energies. As test cases we use a series of small molecules and molecular ions, primarily carbon and nitrogen halides. We find that neglect of chemical binding nearly always reduces the mean excitation energies and that the fully atomic decomposition of any molecule but a diatomic molecule never gives the best fulfilment of Bragg’s rule. The best fulfilment of Bragg’s rule is obtained when as few bonds as possible are broken and when the choice of fragments is guided by chemical knowledge. By investigating several alternative fragmentation patterns for a molecule, guidelines for choice of optimal fragmentation are suggested.

本研究旨在探讨化学键合对布拉格规则在计算阻止截面和平均激发能中的应用有效性的影响。作为测试案例，我们选用了一系列小分子和分子离子，主要涉及碳和氮的卤化物。研究发现，忽视化学键合几乎总是会导致平均激发能的降低，而对于非双原子分子而言，任何分子的完全原子分解均无法达到布拉格规则的完美契合。当尽可能少的键被断裂，且片段的选择受到化学知识的指导时，才能获得对布拉格规则的最好满足。通过研究分子的多种替代分解模式，本研究提出了选择最优分解方式的指导方针。