CAM-B3LYP


Clicked A Few Times
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

Forum Regular
Hi Byrne,

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

Best,
-Niri

Niri Govind
PNNL

Clicked A Few Times
Thank you for your help Niri.

Just Got Here
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.

  • Guest -
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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