| 查看: 1185 | 回复: 1 | |||
| 当前主题已经存档。 | |||
[交流]
【求助】关于casscf方法计算激发态的活性空间选择
|
|||
 大家好，casscf方法计算激发态，最重要的是不是活性空间的选择？怎样选？然后又怎样选择调轨道呢？朋友们了解的，都过来说说你们的认识吧，谢谢。 |
回复此楼» 猜你喜欢
瑞典林雪平大学范立洲课题组现招聘博士后、岗位制博士生
已经有1人回复
-
求有机合成大神指点三硫酸乙烯酯（CAS：2793408-99-6）的合成路线
已经有10人回复
-
物理化学论文润色/翻译怎么收费?
已经有244人回复
-
钯炭、铂炭、钌炭等加氢催化剂
已经有27人回复
-
AgI的FT-IR谱图
已经有1人回复
-
【急招】 北京工业大学 第二批博士申请-杰青课题组1-2名额，25日截止！！
已经有12人回复
-
1，6-己二胺甲基化合成四甲基己二胺
已经有2人回复
-
求助电子版书籍《半导体材料计算》
已经有0人回复
-
气相色谱出峰异常求助
已经有1人回复
-
求助：三乙酰丙酮铁（Fe(acac)₃）标准红外(IR)与XRD谱图/数据
已经有0人回复
coolrainbow
木虫 (著名写手)
未来国家冻凉
- QC强帖: 11
- 应助: 1 (幼儿园)
- 贵宾: 0.1
- 金币: 3979.5
- 散金: 10
- 红花: 50
- 帖子: 1137
- 在线: 272.3小时
- 虫号: 239560
- 注册: 2006-04-07
- 性别: GG
- 专业: 理论和计算化学
★ ★ ★ ★ ★ ★
小木虫(金币+0.5):给个红包，谢谢回帖交流
yjcmwgk(金币+5,VIP+0): 12-29 09:56
小木虫(金币+0.5):给个红包，谢谢回帖交流
yjcmwgk(金币+5,VIP+0): 12-29 09:56
|
How to Choose Active Orbitals? There is no general answer to this question. Attempts have been made but with rather limited success. If you have no idea, choose a large active space and run RASSCF(SDTQ...) with only a small number of orbitals in RAS2. This has to be done on several points on an energy surface. Choose as active the orbitals with occupation numbers > 0:02 or < 1:98. If this is not possible, choose another method. Use the same active space for the whole surface. Excited States of Conjugated Organic Moelcules Use preferably all -orbitals. Add appropriate lone-pair orbitals. Add 3s,3p,3d Rydberg orbitals if the spectrum extends into this region. Note that this requires special basis sets. Sometimes it is necessary to add extra valence orbitals in order to avoid intruder states. Alternatively level shift can be used. Active Spaces in TM compounds For Mn-Cu use preferably 2 orbitals per doubly occupied 3d orbital (the double shell e ect). These may include ligand orbitals for bond forming 3d orbitals. This is enough for d-d transitions in ionic compounds (10 orbitals). If CT transitions, corresponding ligand orbital must be included. Sometimes it is not possible to nd an appropriate active space that is small enough! Core correlation and relativistic e ects are important already for the rst row of TM. |
2楼2009-12-28 17:48:02