FSSH Hopping probability between states

Questions
#1

Hi all

I was playing around with FSSH on ethylene and set the number of allowed surfaces to be 20 (singlets). At the end of each time step there is a “Hopping probability” value, which is self explanatory. What I am wondering is: Is that value the total probability to hop to any allowed state?

Is there any way I can look at the hopping probability to each individual allowed state? In my case its 19 states excluding current state so there should be 19 P_ij values, where i is current state and j is some other state

Thanks in advance for any help

#2

Can you please post a snippet from the output, or maybe a simple input file?

#3

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Attached figure is a screenshot of the .out file with Hopping probability.

Below is the input .inp file:

$molecule
0 1
C 1.85082356 -1.78953123 0.00000000
H 2.38603593 -2.71605577 0.00000000
H 0.78082359 -1.78977646 0.00000000
C 2.52815456 -0.61573833 0.00000000
H 1.99294220 0.31078621 0.00000000
H 3.59815453 -0.61549310 0.00000000
$end

$rem
JOBTYPE freq
METHOD hf
basis 6-31g*
$end

@@@

$molecule
read
$end

$rem
jobtype aimd
exchange hf
basis 6-31g*
cis_n_roots 2
symmetry off
sym_ignore true
cis_singlets true
cis_triplets false
proj_transrot true
fssh_lowestsurface 0
fssh_nsurfaces 2
fssh_initialsurface 1
afssh 0
cis_der_couple true
aimd_steps 600
time_step 10
aimd_short_time_step 2
aimd_time_step_conversion 1
aimd_print 1
aimd_init_veloc zpe
aimd_integration vverlet
$end

#4

There is only 2 surfaces in this case but the issue is still presented. I wish to see the hopping probability from current state to all allowed state.
Thanks again for any help!

#5

Someone who knows this code better can correct me, but after poking around in the code a bit, it does not appear as if this has been implemented in a way that is user-accessible from the input file. You could make a feature request, as it feels like it should be a relatively minor change to the AFSSH code

#6

Thanks for hopping in this, John. You are correct that there is not currently a user-facing method for printing all hopping probabilities. And, as you suggest, it wouldn’t be too difficult to implement.