Are optical forces derived from a scalar potential?

The expression of optical forces provoked by an incident light illuminating particles can be deduced from the Lorentz law. It is shown that these forces derive from a scalar potential in the 2D problem and s-polarization, with light propagating in the cross-section plane of the particles, a fact which shows that the separation between gradient and scattering forces could be questioned. This property does not extend to the p-polarization and 3D problem. In the general case, it is shown that one of the components of the optical force is intimately linked with the reactive energy inside the particle. A possible application is given.