Redlich Kwong Equation Formula

Equation for calculate redlich kwong equation is,

P = (R × T / V_m - b) - [ a / (√T V_m (V_m + b) ) ]

where,
P - the gas pressure,
R - the gas constant,
T - temperature,
V_m - the molar volume (V/n),
a - a constant that corrects for attractive potential of molecules,
b - a constant that corrects for volume