[gmx-users] mdp option for implicit solvent simulation

[Sanku M]

Hi,
  I am trying to do implicit solvent simulation for a protein in gas-phase. I have a few questions :
1) should I use sd integrator?

2) should I also use no periodic condition considering continuum dielectric ?

3) in the JCTC 2010 paper by Lindahl and co-worker, it is mentioned that no cutoffs were used for implicit solvent simulations. 
 But, again in implicit solvent setup the rgblist should be equal to rlist.
Now, if I use rlist=0 ( as all interactions are considered), should I also make rgblist=0?
Does it mean the setup was following type: i.e.
 
  ; NEIGHBORSEARCHING PARAMETERS
; nblist update frequency
nstlist                  = 0
; ns algorithm (simple or grid)
ns-type                  = simple
; Periodic boundary conditions: xyz, no, xy
pbc                      = no
periodic_molecules       = no
; nblist cut-off
rlist                    = 0
; long-range cut-off for switched potentials
rlistlong                = -1

; OPTIONS FOR ELECTROSTATICS AND VDW
; Method for doing electrostatics
coulombtype              = cut-off
rcoulomb-switch          = 0
rcoulomb                 = 0
; Relative dielectric constant for the medium and the reaction field
epsilon_r                = 1
epsilon_rf               = 1
; Method for doing Van der Waals
; Method for doing Van der Waals
vdw-type                 = Cut-off
; cut-off lengths
rvdw-switch              = 0
rvdw                     = 0
; Apply long range dispersion corrections for Energy and Pressure
DispCorr                 = No


; IMPLICIT SOLVENT ALGORITHM
implicit_solvent         = GBSA

; GENERALIZED BORN ELECTROSTATICS
; Algorithm for calculating Born radii
gb_algorithm             = Still
; Frequency of calculating the Born radii inside rlist
nstgbradii               = 1
; Cutoff for Born radii calculation; the contribution from atoms
; between rlist and rgbradii is updated every nstlist steps
rgbradii                 = 0
; Dielectric coefficient of the implicit solvent
gb_epsilon_solvent       = 80
; Salt concentration in M for Generalized Born models
gb_saltconc              = 0.150
; Scaling factors used in the OBC GB model. Default values are OBC(II)
gb_obc_alpha             = 1
gb_obc_beta              = 0.8
gb_obc_gamma             = 4.85
gb_dielectric_offset     = 0.009
sa_algorithm             = Ace-approximation
sa_surface_tension       = -1



Some idea about the implicit solvent setup will be appreciated.
Sanku