The excitation energy on EOM-CCSD QM/MM calculation?
Clicked A Few Times
11:38:17 PM PDT - Sun, Oct 28th 2012
Hi everyone,

I performed EOM-CCSD QM/MM calculation for H2O molecules as a test case. My question is how to get the excitation energy? NWChem does not print it explicitly.

The following is the input file:
start e4h2o

memory total 4500 Mb

charge -1

basis spherical
* library 6-31++g**
end

scf
thresh 1.0e-10

tol2e  1.0e-10

doublet

rohf
end

md 
system e4h2o_opt

cutoff 1.0 qmmm 1.0

noshake solute
end

qmmm
mm_charges expand all
end

tce
freeze atomic core

ccsd

tilesize 8

attilesize 60

2eorb

2emet 14

diis 5

thresh 1.0d-5

nroots 2

eomsol 2

idiskx 1
end

task tce qmmm energy

The following is part of the output file, if you interested in the file, I can email it to you.
EOMCCSD root nr.                     1



Singles contributions

   22a   (alpha) ---    21a   (alpha)        0.8957902018

   25a   (alpha) ---    21a   (alpha)       -0.1010208625

   26a   (alpha) ---    21a   (alpha)        0.1495866218

   27a   (alpha) ---    21a   (alpha)        0.2654077772

   28a   (alpha) ---    21a   (alpha)       -0.1891541423

   34a   (alpha) ---    21a   (alpha)        0.1191698732



Doubles contributions

EOMCCSD root nr.                     2



Singles contributions

   22a   (alpha) ---    21a   (alpha)        0.1078353808

   23a   (alpha) ---    21a   (alpha)        0.8192252691

   24a   (alpha) ---    21a   (alpha)       -0.2875936030

   26a   (alpha) ---    21a   (alpha)       -0.2268543499

   27a   (alpha) ---    21a   (alpha)       -0.3199715289

   29a   (alpha) ---    21a   (alpha)        0.1373032935



Doubles contributions



Parallel integral file used     436 records with       0 large values



Bq nuclear interaction energy =   6.89703372905328     



QM/MM Energy



quantum energy                      -305.169313270 (-.801222E+06  kjoule/mol)

quantum energy adjusted             -305.169313270 (-.801222E+06  kjoule/mol)

quantum energy internal             -312.066346999 (-.819330E+06  kjoule/mol)

Bq-nuclear energy                      6.897033729 (0.181082E+05  kjoule/mol)

Bq-electron energy                     0.000000000 (0.000000E+00  kjoule/mol)

classical energy                      -4.752909506 (-.124788E+05  kjoule/mol)

total qmmm energy                   -309.922222776 (-.813701E+06  kjoule/mol)


Thanks in advance.

Clicked A Few Times
4:15:04 PM PDT - Mon, Oct 29th 2012
The EOMCCSD excitation energies are printed before printing the amplitudes.
Usually it looks like:


EOM-CCSD right-hand side iterations
--------------------------------------------------------------

     Residuum       Omega / hartree  Omega / eV    Cpu    Wall

--------------------------------------------------------------



Iteration   1 using    1 trial vectors

  0.3441834723226   0.4960382793046   13.49789     0.0     0.0



Iteration   2 using    2 trial vectors

  0.0569282647087   0.4422999231339   12.03560     0.0     0.0


..... iterations

Iteration   7 using    7 trial vectors

  0.0000000000000   0.4406555021952   11.99085     0.0     0.0

--------------------------------------------------------------

Iterations converged

largest EOMCCSD amplitudes: R1 and R2



Singles contributions

    6a   (alpha) ---     5a   (alpha)       -0.9481694324



Doubles contributions

    6a   (alpha)     7a   (beta ) ---     3a   (alpha)     5a   (beta )       -0.1062858495

    6a   (alpha)     7a   (beta ) ---     5a   (alpha)     3a   (beta )       -0.1323331866

    7a   (alpha)     6a   (beta ) ---     3a   (alpha)     5a   (beta )       -0.1323331866

    7a   (alpha)     6a   (beta ) ---     5a   (alpha)     3a   (beta )       -0.1062858495


The 0.4406555021952 11.99085 numbers from the last iteration give the EOMCCSD excitation energies in a.u. and in eV.

Best,
Karol

Clicked A Few Times
9:58:48 AM PDT - Fri, Nov 2nd 2012
Quote:Wjb0920 Oct 28th 11:38 pm
Hi everyone,

I performed EOM-CCSD QM/MM calculation for H2O molecules as a test case. My question is how to get the excitation energy? NWChem does not print it explicitly.

The following is the input file:
start e4h2o

memory total 4500 Mb

charge -1

basis spherical
* library 6-31++g**
end

scf
thresh 1.0e-10

tol2e  1.0e-10

doublet

rohf
end

md 
system e4h2o_opt

cutoff 1.0 qmmm 1.0

noshake solute
end

qmmm
mm_charges expand all
end

tce
freeze atomic core

ccsd

tilesize 8

attilesize 60

2eorb

2emet 14

diis 5

thresh 1.0d-5

nroots 2

eomsol 2

idiskx 1
end

task tce qmmm energy

The following is part of the output file, if you interested in the file, I can email it to you.
EOMCCSD root nr.                     1



Singles contributions

   22a   (alpha) ---    21a   (alpha)        0.8957902018

   25a   (alpha) ---    21a   (alpha)       -0.1010208625

   26a   (alpha) ---    21a   (alpha)        0.1495866218

   27a   (alpha) ---    21a   (alpha)        0.2654077772

   28a   (alpha) ---    21a   (alpha)       -0.1891541423

   34a   (alpha) ---    21a   (alpha)        0.1191698732



Doubles contributions

EOMCCSD root nr.                     2



Singles contributions

   22a   (alpha) ---    21a   (alpha)        0.1078353808

   23a   (alpha) ---    21a   (alpha)        0.8192252691

   24a   (alpha) ---    21a   (alpha)       -0.2875936030

   26a   (alpha) ---    21a   (alpha)       -0.2268543499

   27a   (alpha) ---    21a   (alpha)       -0.3199715289

   29a   (alpha) ---    21a   (alpha)        0.1373032935



Doubles contributions



Parallel integral file used     436 records with       0 large values



Bq nuclear interaction energy =   6.89703372905328     



QM/MM Energy



quantum energy                      -305.169313270 (-.801222E+06  kjoule/mol)

quantum energy adjusted             -305.169313270 (-.801222E+06  kjoule/mol)

quantum energy internal             -312.066346999 (-.819330E+06  kjoule/mol)

Bq-nuclear energy                      6.897033729 (0.181082E+05  kjoule/mol)

Bq-electron energy                     0.000000000 (0.000000E+00  kjoule/mol)

classical energy                      -4.752909506 (-.124788E+05  kjoule/mol)

total qmmm energy                   -309.922222776 (-.813701E+06  kjoule/mol)


Thanks in advance.


If i am not mistaken I think you can only do EOM-CCSD for closed-shell systems.

Clicked A Few Times
5:15:16 AM PST - Tue, Nov 13th 2012
Thanks
Thank you Karol for your instruction in reading output file.
Thank you Doudou, I will check my results.


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