CAM-B3LYP

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Hi,
       Currently, I am using the above-mentioned functional for the optimization of metallic nanoparticles. I've noticed that in the test example (h2o-camb3lyp-pol-cdfit.nw) , there is a line "set int:cando_txs f". I get identical results whether I include that line or not. Can anyone tell me what is the function of that line? I could not find it anywhere on the NWChem website. Thank you for your help.

Regards,
Bryne

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Hi Byrne,

You don't need that setting now. This is set this automatically in the code now.

Best,
-Niri

Niri Govind
PNNL

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Thank you for your help Niri.

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CAM-B3LYP TDDFT different results in G09 and Nwchem
Dear NWChem users,

I was wondering if there is some reason why gaussian (g09) and nwchem (6.0 version) are giving different results when using cam-b3lyp to perform a tddft calculation with the input files written below.

These are my input files and the relevant part of the outputs:

g09 input file:

%nproc=4
%mem=6GB
%chk=h2o.chk
  1. P CAM-B3LYP/6-31G* TD=(Nstates=20) scf=(maxcycle=500)

H2O

0 1
O 0.00000000 0.00000000 0.11920704
H 0.75933475 0.00000000 -0.47682817
H -0.75933475 0.00000000 -0.47682817




In output:

Excitation energies and oscillator strengths:

Excited State   1:      Singlet-B1     8.0411 eV  154.19 nm  f=0.0138  =0.000
5 -> 6 0.70696
This state for optimization and/or second-order correction.
Total Energy, E(TD-HF/TD-KS) = -76.0847355115
Copying the excited state density for this state as the 1-particle RhoCI density.

Excited State   2:      Singlet-A2    10.1126 eV  122.60 nm  f=0.0000  <S**2>=0.000
5 -> 7 0.70611
...




nwchem input file:


START h2o_cam
TITLE "CAM-B3LYP/6-31G* H2O"
GEOMETRY
O 0.00000000 0.00000000 0.11920704
H 0.75933475 0.00000000 -0.47682817
H -0.75933475 0.00000000 -0.47682817
END
BASIS
* library 6-31G*
END
DFT
xc xcamb88 1.00 lyp 0.81 vwn_5 0.19 hfexch 1.00
cam 0.33 cam_alpha 0.19 cam_beta 0.46
direct
iterations 800
END
TDDFT
RPA
NROOTS 20
SINGLET
NOTRIPLET
TARGET 1
END
TASK TDDFT ENERGY



In output file:

 -------------------------------------------------------
Root 1 singlet b2 0.076745878 a.u. ( 2.0883625 eV)
-------------------------------------------------------
Transition Moments X 0.00000 Y -0.26940 Z 0.00000
Oscillator Strength 0.00371

    Occ.  4  a1  ---  Virt. 10  b2   0.05970 Y
Occ. 5 b2 --- Virt. 6 a1 -0.98434 X
Occ. 5 b2 --- Virt. 9 a1 -0.16505 X
Occ. 5 b2 --- Virt. 13 a1 0.09073 X
-------------------------------------------------------

Could anybody shed light on this issue? Is anything wrong with my input file?

Thanks in advance,

Pablo.

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Hi Pablo,

Gaussian could be using different default parameters for CAM-B3LYP. Our parameters are given in the documentation.

If you know how CAM-B3LYP is defined in Gaussian 09, you should be able to reproduce those results with NWChem.

Best,
-Niri


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