I am trying to look into the change in energy for molecules in an electric field. Below I have included my input for hydroxide where I apply a dipole field in the +x and -x directions. I also don’t apply a field. I am confused, however, because the dipole moment of OH- points along +x (in the chosen orientation), so I would expect a positive field to lower the energy of the system. The calculation indicates the opposite though. A negative field lowers the energy of the system and a positive field raises the energy of the system. Can someone provide me some clarity on this? I can’t find anything in the manual about this, so I assume there is some implicit sign convention I am not understanding. Is that true?

Thanks.

$molecule

-1 1

O 0.0 0.0 0.0

H 0.9591126269 0.0 0.0

$end

$rem

mem_total 16000

ideriv 1

incdft 0

incfock 0

jobtype sp

method wB97X-V

unrestricted false

basis def2-qzvppd

scf_algorithm gdm

scf_max_cycles 500

scf_guess sad

scf_convergence 8

thresh 14

symmetry 0

sym_ignore 1

gen_scfman true

gen_scfman_final true

internal_stability false

complex false

chelpg true

$end

$multipole_field

X -0.001

Y 0.0

Z 0.0

$end

@@@

$molecule

-1 1

O 0.0 0.0 0.0

H 0.9591126269 0.0 0.0

$end

$rem

mem_total 16000

ideriv 1

incdft 0

incfock 0

jobtype sp

method wB97X-V

unrestricted false

basis def2-qzvppd

scf_algorithm gdm

scf_max_cycles 500

scf_guess sad

scf_convergence 8

thresh 14

symmetry 0

sym_ignore 1

gen_scfman true

gen_scfman_final true

internal_stability false

complex false

chelpg true

$end

$multipole_field

X 0.001

Y 0.0

Z 0.0

$end

@@@

$molecule

-1 1

O 0.0 0.0 0.0

H 0.9591126269 0.0 0.0

$end

$rem

mem_total 16000

ideriv 1

incdft 0

incfock 0

jobtype sp

method wB97X-V

unrestricted false

basis def2-qzvppd

scf_algorithm gdm

scf_max_cycles 500

scf_guess sad

scf_convergence 8

thresh 14

symmetry 0

sym_ignore 1

gen_scfman true

gen_scfman_final true

internal_stability false

complex false

chelpg true

$end