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2025-07-04 12:01:42 +08:00
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2 changed files with 16 additions and 16 deletions

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@@ -13,23 +13,22 @@ This approximation is based on the fact that
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。 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。 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] 12 个表示; 18 Gamma 点的弱极性声子包含了 C#sub[6v] 点群的12 个不可约表示(2A#sub[1] + 4B#sub[1] + 2E#sub[1] + 4E#sub[2])。
中简并表示E1 E2的拉曼张量的形状可以通过进一步考虑 C#sub[2v] 点群中的表示确定,如表所示。 通过进一步考虑 C#sub[6v] 中简并表示E1 E2 C#sub[2v] 中的表示,所有声子的拉曼张量的非零分量可以确定,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。 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。 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.) The form of the Raman tensors (i.e., which components are non-zero) could be determined by symmetry analysis.
Phonons at the #sym.Gamma point satisfy the C#sub[6v] point group symmetry, The 18 negligible-polar phonons at the #sym.Gamma point
and the 18 negligible-polar phonons correspond to 12 irreducible representations of the C#sub[6v] point group: correspond to twelve irreducible representations of the C#sub[6v] point group
2A#sub[1] + 4B#sub[1] + 2E#sub[1] + 4E#sub[2]. (2A#sub[1] + 4B#sub[1] + 2E#sub[1] + 4E#sub[2]).
Phonons belonging to the A#sub[1] and B#sub[1] representations vibrate along the z-axis and are non-degenerate, By further considering the doubly degenerate modes of the C#sub[6v] (E#sub[1] and E#sub[2])
while those belonging to the E#sub[1] and E#sub[2] representations vibrate in-plane and are doubly degenerate. in the C#sub[2v] point group,
Phonons of the B#sub[1] representation are Raman-inactive, as their Raman tensors vanish. the form of the 18 negligible-polar phonons' Raman tensors can be determined, as shown in @table-rep.
In contrast, phonons of the other representations are Raman-active, Phonons of the B#sub[1] representation in C#sub[6v] have a zero Raman tensor and do not contribute to Raman scattering,
and the non-zero components of their Raman tensor while other phonons have non-zero Raman tensor components,
can be determined by further considering their representation in the C#sub[2v] point group (see @table-rep). indicating they may be observable in Raman experiments under appropriate incidence and polarization configurations.
These Raman-active phonons are potentially be visible in Raman experiment under appropriate polarization configurations.
However, whether a mode is sufficiently strong to be experimentally visible However, whether a mode is sufficiently strong to be experimentally visible
depends on the magnitudes of its Raman tensor components, depends on the magnitudes of its Raman tensor components,
which cannot be determined solely from symmetry analysis. which cannot be determined solely from symmetry analysis.

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@@ -16,6 +16,7 @@
- [x] 英文 - [x] 英文
- [x] 调整语言 - [x] 调整语言
- [ ] 坐标轴定义 - [ ] 坐标轴定义
- [ ] 偏振
- [x] 模型总述 - [x] 模型总述
- [x] 无缺陷和点缺陷的模型大小、结构 - [x] 无缺陷和点缺陷的模型大小、结构
- [x] 中文 - [x] 中文
@@ -48,9 +49,9 @@
- [x] 中文 - [x] 中文
- [x] 英文 - [x] 英文
- [x] 调整语言 - [x] 调整语言
- [ ] 表示 - [/] 表示
- [ ] 中文 - [x] 中文
- [ ] 英文 - [x] 英文
- [ ] 调整语言 - [ ] 调整语言
- [ ] 估算拉曼张量 - [ ] 估算拉曼张量
- [ ] 中文 - [ ] 中文