Single Run

Inorder to make FIREBALL to run a MDET simulation, one has to have a fireball.in, mdet.input, gamma.kpts, input.bas, VELOCITES. The input.bas and VELOCITES will be gathered from MD run.

fireball.in

&option
basisfile=input.bas 
iensemble = 3
iquench = 0
nstepi = 1
nstepf = 4000
iqout = 1
icluster = 1
dt = 0.25
T_initial = 300.0
rescal = 1.00
tempfe = 300
sigmatol = 1.00E-05
imdet = 1
nddt = 100
&end
&output
iwrtxyz = 1
iwrtpop = 1
iwrtvel = 0
iwrteigen = 0
iwrtefermi = 1
iwrtfpieces = 0
&end

The important parts here are to set imdet = 1, set initial and final steps in nstepi and nstepf, set dt, and the Temprature.

mdet.input

If we set imdet = 1 we need a “mdet.input” file. This file will contain the state and the occupations of them. So first we have to find the number of the last state ocuupied (HOMO). Inorder to do that one can check number of electrons in our system from log file of MD, this value will be denoted as ztot, so one can either open the log file and look for ztot or use the grep command (grep <text> <filename>)
example :

  $ grep ztot log
  $  (What it must be)           ztot =    68.0000000000000

Now since each state can be occupied by two electrons, we can divide the number of electrons by 2, if the remainder of this division is equal two zero that means that HOMO is fully occupied, meaning \(HOMO = (ztot)/2\), If the remainder is equal to one it means that the HOMO is half occupied, so we take the quotient of \((ztot)/2\) and add 1 to it. for example if ztot is 10 \(HOMO = 5\), but if it is 11, the quotient(11/2)=5 so \(HOMO = 6\). Or in azobenzene if ztot is 68, that means HOMO is equal to 34 and it’s fully occupied, If we one to excite one electron in LUMO the mdet will have 34 having 1 electron in it and 35 another one.

The mdet.input file starts with number of states, next the states with their occupation, for example for azobenzene with one electron excited in LUMO we have :

2                                 ! nele (number of states where switches are possible)
34  1
35  1

gamma.kpts

1
0 0 0 1.0

The next step will be to copy the fireball.x and Fdata or make a soft link to the Fdata and run ./fireball.x