All interactions between photons and matter are described as series of absorptions and emissions of photons. When an arriving photon strikes a single molecule at the surface of a material, is absorbed and almost immediately reemitted, the ‘new’ photon may be emitted in any direction, thus causing diffuse reflection.[citation needed]
Specular reflection (following Hero's equi-angular reflection law) is a quantum mechanical effect explained as the sum of the most likely paths the photons can take. Light–matter interaction is a topic in quantum electrodynamics, and is described in detail by Richard Feynman in his book QED: The Strange Theory of Light and Matter.
The energy of the incoming photon may match the energy required to change the molecule from one state to another, causing a transition in kinetic, rotational, electronic or vibrational energy. When this occurs, the photon may not be reemitted or alternatively may be reemitted with a loss of energy. These effects are known as Raman, Brillouin and Compton scattering.
.Oh, I might add - air has very little absorption mostly because it's far less dense than a solid. In my early education, that corresponds to a very very low decay/absorption constant (look up the exponential law of absorption). Whereas, with a solid there is a much higher chance of absorption.
