Energy barrier of proton transfer through MoS2 monolayer
I am attempting to determine the energy barrier for proton transfer through MoS2 using a static energy barrier calculation approach. I am varying the position of the proton relative to the surface. My goal is to replicate the results of a paper titled "Proton and hydrogen transport through two-dimensional monolayers." I obtained an energy well of 1.06 eV, while the paper reports it as 1.56 eV. Do you have any suggestions on what I should investigate to reconcile this difference?
ISTART = 0
ICHARG = 2
ISIF = 2
PREC = Normal
ALGO = Normal
ISYM = 0
LREAL = Auto
IBRION = 2
POTIM = 0.2
ENCUT = 400
ISMEAR = 0
SIGMA = 0.05
EDIFF = 1E-5
EDIFFG = -0.02
NSW = 300
NELM = 300
NELMIN = 5
IVDW = 11
ISPIN = 1
LWAVE = .FALSE.
LCHARG = .FALSE.
NELECT = 702 ( 27 Mo (ZVAL=14), 54 S (ZVAL=6), 1H+)