I’m trying to calculate excited states of H2O+ and print out their energies within each irrep (eom-ccsd). I can print out the total energy of each root by accessing the CCSD ROOT *n* TOTAL ENERGY variable, but trying the other variables that are proposed fails. The following variables

CCSD ROOT *n* (IN *h*) TOTAL ENERGY

CCSD ROOT *n* (*h*) TOTAL ENERGY

CCSD ROOT *n* TOTAL ENERGY - *h* TRANSITION

are not set, for example.

Am I missing something to set these variables, or is there a better way to go about doing this ?

```
set puream true
set print_MOs true
molecule H2OX {
1 2
symmetry C2v
units ang
# no_com # do not adjust centre of mass
# no_reorient # do not adjust orientation of the molecule
O
H 1 R
H 1 R 2 angle
R = 1.01
angle = 108.8
}
# -- HF
set basis cc-pVTZ
set reference rohf
set maxiter 100
# -- EOM-CC2
set eom_reference rohf
set roots_per_irrep [ 1, 1, 1, 1 ]
nRoots = 4
# nRoots = 20
# -- multithread
from multiprocessing import cpu_count
nproc = cpu_count()
set_num_threads(nproc)
nθ = 2
θi = 60
θf = 61
dθ = (θf - θi) / (nθ - 1)
angles = [ θi + i * dθ for i in range(0,nθ) ]
for θ in angles:
H2OX.angle = θ
energy('eom-ccsd')
print(str(θ)+" " ,end="")
# for n in range(0,nRoots) :
for n in range(0,5) :
for h in range(1,5) :
var="CCSD ROOT " + str(n) + " TOTAL ENERGY"
# var="CCSD ROOT " + str(n) + " (IN " + str(h) + ") TOTAL ENERGY"
# var="CCSD ROOT " + str(n) + " TOTAL ENERGY - " + str(h) + " TRANSITION"
print(str(variable(var))+" ", end="")
print("")
```

Running the above code with the line

```
var="CCSD ROOT " + str(n) + " TOTAL ENERGY"
```

works fine, but crashes when either of the two lines below

```
# var="CCSD ROOT " + str(n) + " (IN " + str(h) + ") TOTAL ENERGY"
# var="CCSD ROOT " + str(n) + " TOTAL ENERGY - " + str(h) + " TRANSITION"
```

are uncommented because of the unset variables.

Any help is appreciated.

Variables referenced from the PSI Variables by Alpha page

https://psicode.org/psi4manual/master/glossary_psivariables.html