The mean excitation energy $〈I〉$ is a fundamental quantity in radiation physics, concerning energy deposition in matter and absorbed dose analytical estimations for charged particles. The stopping of charged particles in different materials strongly depends on this parameter among others. This work intends to contribute with insights for some issues, usually treated not in detail in the theory of stopping power, as the analytic and theoretic assessment of $〈I〉$-value for different relevant materials. A methodology is proposed and described aimed at providing the procedure for the $〈I〉$ calculation framework, based on the definition of the mean excitation energy using the dielectric response function is analytically integrable if the inelastic cross section parameters are known. Some dielectric models were studied, aimed at calculating the $〈I〉$-value for liquid water by theoretical means, reaching the conclusion that a decay at least of the order of ${\omega }^{-2}$ in frequency (energy) is needed as weak condition of the optical energy-loss function for the integrals to converge. Afterwards, the first four discrete excitation levels and the diffuse bands for water are treated in a fully analytical scheme, and further compared with numerical results, providing the contribution of these levels to $〈I〉$, with the aim of testing the proposed analytical model.

平均激发能 $〈\mathrm{一世}〉$是辐射物理学中的基本量，涉及物质中的能量沉积和带电粒子的吸收剂量分析估计。不同材料中带电粒子的阻止尤其取决于此参数。这项工作旨在为某些问题的见解做出贡献，这些问题通常在制动力的理论中未作详细论述，作为对动力的分析和理论评估。$〈\mathrm{一世}〉$-不同相关材料的价值。提出并描述了一种方法，旨在为$〈\mathrm{一世}〉$如果已知非弹性截面参数，则基于介电响应函数的平均激发能定义的计算框架在分析上是可积分的。研究了一些介电模型，旨在计算$〈\mathrm{一世}〉$通过理论方法获得液态水的-值，得出的结论是，衰减至少为 ${\omega }^{-2}$频率（能量）的变化是必要的，因为积分的光学能量损失函数处于弱状态。之后，在完全分析方案中处理了水的前四个离散激发能级和扩散带，并与数值结果作了进一步比较，从而提供了这些能级对水的贡献。$〈\mathrm{一世}〉$，目的是测试所提出的分析模型。