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kingleaves

金虫 (小有名气)

[求助] 激发态计算

问题是这样的,一篇文章写到excited at 340nm,那我做计算的话,激发态是不是该选与这个值比较接近的root来做激发态的优化,进而计算荧光?而不去考虑计算中的谐振强度f的大小。也就是说已经有了实验激发波长的话该如何计算荧光呢?在此先谢过各位了。
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nwwolfchj

金虫 (正式写手)

不是吧,要根据这个态的对称性,第几个激发态综合考虑吧,实验和理论不一定完全吻合,理论上有时候有多个接近的态,这时候又要理论和实验的归属一致,才能比较。一定要本质一致,负责拿个值相近其实根本不是一回事的态去做,即使作出来也是错的。
2楼2011-12-26 01:28:13
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kingleaves

金虫 (小有名气)

引用回帖:
: Originally posted by nwwolfchj at 2011-12-26 01:28:13:
不是吧,要根据这个态的对称性,第几个激发态综合考虑吧,实验和理论不一定完全吻合,理论上有时候有多个接近的态,这时候又要理论和实验的归属一致,才能比较。一定要本质一致,负责拿个值相近其实根本不是一回事 ...

那请问实验的方法怎么来确定电子态的对称性呢?谢谢,对于实验不是很了解。看到文章中都只是算了第一激发态,且f值都挺大的,但是在我自个的计算中第一激发态有些f值很小,不知道该如何下手了。不知道我说明白了没。谢谢
3楼2011-12-26 16:43:25
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tomhy

铜虫 (初入文坛)

【答案】应助回帖

感谢参与,应助指数 +1
in the experiment, we usaually use single excitation to irradiate the sample to get the emission spectrum, such as flourescence and phosphorescence. In this case, I will calculate the UV-Vis absorption of the ground state molecule to see if there is overlap between the calculated absorption band and exictation light at 340nm. I believe there is.
The phosphorescence is the emission spectrum from triplet state T1 to ground state. so, no matter what the excitation light you used, if there is phosphorescence emission, the spectrum should be the same for the same molecule.

this is my 2 cents.
4楼2011-12-28 00:24:38
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kingleaves

金虫 (小有名气)

引用回帖:
: Originally posted by tomhy at 2011-12-28 00:24:38:
in the experiment, we usaually use single excitation to irradiate the sample to get the emission spectrum, such as flourescence and phosphorescence. In this case, I will calculate the UV-Vis absorp ...

谢谢你的回复,可是还有个疑问是,就像你所说的,其实荧光是从第一激发态下来的,那像高斯里的对于其他态的优化,意义又在于哪里呢?谢谢
5楼2011-12-28 19:27:45
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tomhy

铜虫 (初入文坛)

【答案】应助回帖

引用回帖:
5楼: Originally posted by kingleaves at 2011-12-28 19:27:45:
谢谢你的回复,可是还有个疑问是,就像你所说的,其实荧光是从第一激发态下来的,那像高斯里的对于其他态的优化,意义又在于哪里呢?谢谢

The absorption and emission of light direct correlate to the energy differences between the state. Think about how can you get the full uv-vis absorption spectrum from calculation for a molecule. For emission, we match the first excitation to the experimental data. (I might be wrong.) If you read something about dual photon excitation, that will give you a better understanding to your question.
6楼2011-12-28 21:56:10
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