Author Topic: ATK2008.10 questions about:molecular energy spectrum  (Read 7421 times)

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Offline youngjfly

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ATK2008.10 questions about:molecular energy spectrum
« on: November 18, 2010, 06:44 »
After calculating the molecular energy spectrum with the initial spin has been given to the molecule,in the output result,how can i identify which is the HOMO energy(just the negative value below zero?)and the LUMO energy(the first positive value up zero? )of two different spin electrons。
thank you for your attention。

大家算过的给点意见啊,谢谢啦。就是 分子中不同自旋的电子的费米能级也是一样的吗?homo-lumo是用 零值左右的正负值来表示? 我算出的费米能级是负值,并且上面还有几个负值的能级。应该怎么理解呢?

期待。急用,谢谢大家。

Thank all of you  again
.................................

Offline zh

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Re: ATK2008.10 questions about:molecular energy spectrum
« Reply #1 on: November 18, 2010, 12:13 »
Of course, the Fermi level for the molecular energy levels of up-spin and down-spin are same. Usually, the positions of HOMO and LUMO are determined by the  corresponding electron occupations, rather than the sign of energy values (i.e., negative or positive). Only the energy zero is set as the Fermi level, you can find out the positions of HOMO and LUMO by the sign of  their respective values.  The first eigenvalue of molecular orbitals below the Fermi level corresponds to the HOMO, and the first eigenvalue of molecular orbital above the Fermi level corresponds to the LUMO.

Offline youngjfly

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Re: ATK2008.10 questions about:molecular energy spectrum
« Reply #2 on: November 19, 2010, 04:47 »
Of course, the Fermi level for the molecular energy levels of up-spin and down-spin are same. Usually, the positions of HOMO and LUMO are determined by the  corresponding electron occupations, rather than the sign of energy values (i.e., negative or positive). Only the energy zero is set as the Fermi level, you can find out the positions of HOMO and LUMO by the sign of  their respective values.  The first eigenvalue of molecular orbitals below the Fermi level corresponds to the HOMO, and the first eigenvalue of molecular orbital above the Fermi level corresponds to the LUMO.
but after i calculated the Fermi energy ,it shows 
                  ......................................
                  ......................................               
                93.79                  93.80
                94.94                  94.94
                94.95                  94.95
                94.97                  94.98
                94.98                  94.99
                95.25                  95.28
                97.35                  97.36
                98.01                  98.03
Fermi energy
-1.80426204477 eV

then the HOMO energy is a bit smaller one than -1.80426204477 eV?
and the LUMO energy is a bit bigger one than -1.80426204477 eV?  without comparing them with 0ev??? ???

Offline zh

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Re: ATK2008.10 questions about:molecular energy spectrum
« Reply #3 on: November 19, 2010, 09:47 »
谢谢你啊,好悲剧啊。..................
Please remove your Chinese comment!

Offline zh

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Re: ATK2008.10 questions about:molecular energy spectrum
« Reply #4 on: November 19, 2010, 09:50 »
Please show the eigenvalues of molecule orbitals around the Fermi energy.

Offline zh

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Re: ATK2008.10 questions about:molecular energy spectrum
« Reply #5 on: November 19, 2010, 09:54 »
...
Fermi energy
-1.80426204477 eV

then the HOMO energy is a bit smaller one than -1.80426204477 eV?
and the LUMO energy is a bit bigger one than -1.80426204477 eV?  without comparing them with 0ev??? ???
Just from the results shown by you, the answer is yes.

Offline youngjfly

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Re: ATK2008.10 questions about:molecular energy spectrum
« Reply #6 on: November 20, 2010, 08:40 »
...
Fermi energy
-1.80426204477 eV

then the HOMO energy is a bit smaller one than -1.80426204477 eV?
and the LUMO energy is a bit bigger one than -1.80426204477 eV?  without comparing them with 0ev??? ???
Just from the results shown by you, the answer is yes.
well, thak you very much. :D