  The modulational instability (MI) of ion-acoustic (IA) waves (IAWs) and
associated IA rogue waves (IARWs) in double pair plasma containing
non-extensive electrons, iso-thermal positrons, negatively and positively
charged ions have been governed by the standard nonlinear Schr\"{o}dinger
equation (NLSE). It has been figured out from the numerical study of NLSE that
the plasma system holds modulationally stable (unstable) region in which the
dispersive and nonlinear coefficients of the NLSE have the opposite (same)
signs. It is also found that the fundamental features of IAWs (viz., MI
criteria, amplitude and width of the IARWs, etc.) are rigorously organized by
the plasma parameters such as mass, charge state, and number density of the
plasma components. The existing outcomes of our present study should be helpful
for understanding the nonlinear features of IAWs (viz., MI and IARWs) in both
laboratory and space plasmas.
