Transmission, absorption, and reflection of light
While I can't explain the phenomenon of light transmission, I can say a few things. The energy levels correlating to physical states and the gaps between the states are quantized. This an all or nothing reaction. The frequency of light must exactly match the energy (E=hv) needed for the excitation event (electron is pushed into a higher orbital, a vibrational mode to expressed, etc) for absorption to occur. When the light frequency is mismatched and does not absorb, it will reflect. The frequency that induces excitation is theoretically the frequency of emission, but phenomena such as intersystem crossing may create multiple paths by which the excitation energy will disperse. Hope this helped.