Abstract
Existing theories for the surface-tension-driven Bénard convection (Marangoni convection) have considered only thermocapillary effects through the shear stress balance equation at the interface via the surface-tension-gradient-induced shear stresses. Thermocapillary induced surface energy variation has been ignored altogether in these theories. A formulation taking into account this surface energy variation shows that it can have a non-negligible effect on the onset of Bénard convection cells.