[molpro-user] Ask help on molpro calculation as a new user

[Yin,Shi]

Dear Molpro folks,

I am, Shi Yin, working in Prof. Elliot Bernstein group, Chemistry department at Colorado State University. Recently, I start to use molpro to do calculation on iron sulfur negative ion clusters.

I am trying to do calculations of their theoretical first vertical detachment energies (VDE = E neutral at optimized anion geometry - E optimized anion). I start with FeS- as a test firstly.

The following is my input file:

***,FeS-



memory,400,M

gprint

symmetry,nosym

geometry={

2

FeS

 Fe                -0.33994333    0.04249292    0.00000000

 S                  1.83005667    0.04249292    0.00000000

}



basis=TZVP



{uhf

wf,spin=3,charge=-1}

optg                                    !geometry optimization of quartet anion FeS- using hf

{uhf

wf,spin=2,charge=0}       !single point energy of triplet neutral FeS with above optimized geometry of quartet anion FeS- using hf

{uhf

wf,spin=4,charge=0}    !single point energy of quintet neutral FeS with above optimized geometry of quartet anion FeS- using hf



---



The result I obtained is:

        UHF-SCF         UHF-SCF        OPTG(UHF)        UHF-SCF

  -1659.77314480  -1659.70612062  -1659.86274040  -1659.85196075



Thus, I can obtain the VDE = -1659.77314480  - (-1659.86274040) = 0.0895956 Hartree = 2.438 eV.



And then, I did the same thing using B3lyp and TZVP.

The input:

***,FeS-



memory,400,M

gprint

symmetry,nosym

geometry={

2

FeS

 Fe                -0.33994333    0.04249292    0.00000000

 S                  1.83005667    0.04249292    0.00000000

}



basis=TZVP



{uks,b3lyp

wf,spin=3,charge=-1}

optg

{uks,b3lyp

wf,spin=2,charge=0}

{uks,b3lyp

wf,spin=4,charge=0}

---

The results:

        UKS-SCF         UKS-SCF        OPTG(UKS)        UKS-SCF

  -1661.78663123  -1661.76503538  -1661.76845789  -1661.76799811


Thus, I can obtain the VDE = -1661.78663123  - (-1661.76845789) = -0.01817334 Hartree = -0.494 eV.

Because I used Gaussian previously, I compared obtained results with Gaussian, and experimental results, as listed in the following table.




Molpro


Gaussian





hf/TZVP


B3lyp/TZVP


hf/TZVP


B3lyp/TZVP


Calculated VDE of quartet anion FeS- (ground state)


2.438 eV


-0.494 eV


0.83 eV


1.43 eV


Experimental VDE of anion FeS-


1.85 eV




I am confused, because the results obtained by Molpro are very different with that obtained by Gaussian, and the Gaussian results seems more reasonable comparing with the experimental result.

Since I am a new user of Molpro, I am not sure my Molpro calculations are right or not. Could someone help me to check my input file to see if there is any problem or mistake?

Or please feel free to let me know any comments and suggestions to understand the above results listed in the table.

I will appreciate your reply and help very much!



Best regards,



Shi Yin


--
Shi Yin
Web site: http://sites.chem.colostate.edu/bernsteinlab/SY.htm
Department of Chemistry
Colorado State University
Fort Collins, CO 80523
Phone Numbers: Office 970-491-5741; Lab -5787
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