[Octopus-users] Problem with a TDDFT run

Jessica Mecier jessica.mecier at gmail.com
Thu Jul 17 23:40:04 WEST 2008

```                  Dear all,

I am a new octopus user, and I am firstly interested to the computation
of the ionization probability. To begin with, I took the case of CO2 (for
sure, it not the easiest!!!).

1- After some efforts, I have managed (probably a grid problem) to obtain a
ground state where the HOMO(s)  are degenerate, as expected due to the lone
pair on the oxygen atom and the eigenvalues make some senses, but

a)            Certain values of the density are higher than 1, why??

b)            It possible to perform my calculation in cylinder coordinates?
All my tests didn't work. Is it another way in other coordinate?

2- With the above ground state, I didn't succeed to perform TDDFT run using
Ti:Sapphire laser pulse, could someone gives some advices to solve the
problem of the grid for the simple case of CO2???.

3- Is it a way to obtain the orbital ionization probability (HOMO for
example?)

Any help would be very appreciated

Best regards

(UDM), PhD student

Input File (1)

CalculationMode = gs

Units = atomic

UnitsInput = atomic

UnitsOutput = atomic

BoxShape = parallelepiped

%Lsize

10|10|10

%

%spacing

0.20|0.20|0.20

%

#spacing = 0.4

XYZCoordinates = "co2.xyz"

### Functional###

XCfunctional = hyb_gga_xc_x3lyp

### END ######

#AbsorbingBoundaries = 1

### calculation mode unocc ####

#NumberUnoccStates=10

#EigenSolverMaxIter = 3000

###

### LASER MODE ###

TDEvolutionMethod = aetrs

TDMaximumIter = 25000

TDTimeStep = 0.03

amplitude = 0.292577677

omega = 0.05841455

tau0 = 314

t0 = 321

%TDExternalFields

electric_field | 0 | 0 | 1 | envelope_cosinusoidal | amplitude | omega |
tau0 | t0

%

#####

#### OUTPUTFILE####

TDOutput = laser + multipoles + populations + td_occup

OutputEvery=5000

Output = wfs + density + elf + potential

OutputHow = matlab + gnuplot + plane_x + plane_y

################### co2.xyz#######################

3

geometry co2

C         0.000000    0.000000    0.000000

O         0.000000    0.000000   -2.197583134951474

O         0.000000    0.000000    2.197583134951474

###############################################

Density Output (y=0, x, z) (gs calculation)

#         x                      z                     Re
Im

-0.40000000000000      -3.00000000000000       0.50989211235912
0.00000000000000

-0.40000000000000      -2.80000000000000       0.77536254649909
0.00000000000000

-0.40000000000000      -2.60000000000000       0.98931780611781
0.00000000000000

-0.40000000000000      -2.40000000000000       1.01600096674999
0.00000000000000

-0.40000000000000      -2.20000000000000       0.93931436477524
0.00000000000000

Input(2)  Td run

- I thought that the following block should be fine for my propagation,

%Lsize

30|30|100
%

%spacing

0.20|0.20|0.20

# increasing the spacing doesn't change (memory allocation problem),