There are four ²⁹Si NMR experimental studies published for glasses containing ~40 mol% Na₂O and the reported Q species abundances are remarkably consistent. These results have been used to determine accurate Raman Q³ and Q² cross sections for a 40.1 mol% Na₂O glass. The Q³ and Q² cross sections are respectively 1.10 and 0.95 (±0.03). The Q² band of the Raman spectrum is dominantly Lorentzian in shape whereas the Q³ band is asymmetric and based on other studies, the asymmetry increases with alkali content, due primarily to alkali-BO interactions. As explanation, increase in alkali content enhances preferentially electron density over Si atoms of tetrahedra, thereby weakening Si-O coulombic interactions (i.e., force constants), which shifts the symmetric stretch of the Q³ species to lower frequencies, producing asymmetric Q³ line shapes. With Q² and Q³ cross sections established, the high resolution of Raman spectroscopy now can be used to provide highly accurate estimates of Q species in silicate glasses and melts.

对于含约40 mol％Na ₂ O的玻璃，发表了四项²⁹ Si NMR实验研究，报道的Q物种丰度非常一致。这些结果已用于确定40.1摩尔％Na ₂ O玻璃的准确拉曼Q ³和Q ²横截面。Q ³和Q ^2的横截面分别为1.10和0.95（±0.03）。拉曼光谱的Q ²带主要是洛伦兹形状，而Q ³带是不对称的，并且根据其他研究，不对称性随碱含量的增加而增加，这主要是由于碱-BO相互作用。作为解释，碱含量的增加优先于四面体的Si原子提高电子密度，从而减弱Si-O库仑相互作用（即力常数），从而将Q ³物种的对称拉伸移至较低频率，从而产生不对称Q ³线形状。建立了Q ²和Q ³横截面后，拉曼光谱的高分辨率现在可用于提供高度准确的硅酸盐玻璃和熔体中Q物种的估算值。