There are materials which absorb photon of shorter wavelength and emit photons of longer wavelength. Can there be stable substances which absorb photons of larger wavelength and emit light of shorter wavelength.

Explanation

In the first case, the energy of the photon incident on a material is more and the energy of emitted photon is less. In the second case, the energy of the incident photon is less and the energy of the emitted photon is more . For this to happen , the material must supply the energy for the the emission off photon In case of stable substances, this is not likely to happen.