paper/result/perfect/non-polar/default.typ

@@ -1,24 +1,24 @@
 === Phonons with Negligible Polarities
 
-我们用 gamma 点的声子来近似弱极性的声子。
+用 gamma 点的声子来近似。
 
-Gamma 点的声子被用于
+Gamma 点的声子被用于近似参与拉曼散射的弱极性声子，无论入射配置。
+这个近似是因为这些声子的色散曲线在 Gamma 点附近连续且非常接近 Gamma 点，并且已经被广泛使用。
 
-// We investigate phonons at Gamma instead of the exact location near Gamma.
-Phonons at the #sym.Gamma point were used
-  to approximate negligible-polar phonons that participating in Raman processes
+Phonons at the #sym.Gamma point were used to approximate negligible-polar phonons,
   regardless of the wavevector of the incident and scattered light.
-This approximation is widely adopted (cite) and justified by the fact that,
-  although the phonons participating in Raman processes are not these strictly located at the #sym.Gamma point,
-  they are very close to the #sym.Gamma point in reciprocal space
-    (about 0.01 nm#super[-1] in back-scattering configurations with 532 nm laser light,
-    which corresponds to only 1% of the smallest reciprocal lattice vector of 4H-SiC,
-    see orange dotted line in @figure-discont),
-  and their dispersion at #sym.Gamma point is continuous with vanishing derivatives.
-Therefore, negligible-polar phonons involved in Raman processes
-    have nearly indistinguishable properties from those at the #sym.Gamma point.
+This approximation is based on the fact that
+    the dispersion of these phonons is continuous and very close to the #sym.Gamma point,
+  and has been widely adopted in the literature @_n-sic_2008.
 
-gamma 点处 18 个声子的表示。它们的拉曼张量的形状可以确定，但大小无法确定。
+18 个声子属于 12 个表示。拉曼张量的形状可以确定，大小不能。
+
+这些声子的拉曼张量的形状可以通过对称性分析来确定。
+Gamma 点声子满足 C#sub[6v] 点群对称性，18 个模式包含了 2A#sub[1] + 4B#sub[1] + 2E#sub[1] + 4E#sub[2] 共 12 个表示；
+  其中简并表示（E1 和 E2）的拉曼张量的形状可以通过进一步考虑在 C#sub[2v] 点群中的表示来确定，如表所示。
+其中，B#sub[1] 模式具有零拉曼张量，不参与拉曼散射；
+  其它表示的模式具有非零拉曼张量分量，可能可以在适当的偏振配置下在拉曼实验中观察到。
+然而，模式是否足够强以在实验中可见取决于其拉曼张量分量的大小，而仅通过对称性分析无法确定这些大小。
 
 // Representation of these 18 phonons, and the shape of their Raman tensors could be determined in advance.)
 Phonons at the #sym.Gamma point satisfy the C#sub[6v] point group symmetry,