obj = CDrudeModel(fCollisionTime, fChargeMass)
 obj = CDrudeModel(fCollisionTime, fChargeMass, fChargeValue)
 
   fChargeValue - default elementary charge.
  
  note that the mass and Eg depends on the direction of charge
  propagation (which is perpendicular to the light propagation
  direction and is along the polarization direction).