Final answer:
The absorbance of a photon by a molecule involves a transition of an electron from a lower energy ground state to a higher energy excited state, which is a fundamental concept in electronic spectroscopy. This process requires that the energy of the absorbed photon precisely matches the energy difference needed for the electron transition.
Step-by-step explanation:
Yes, the simple absorbance of a photon by a molecule typically involves transitions between different electronic states, usually from a lower energy ground state to a higher energy excited state. When a photon with an energy equivalent to the energy difference (ΔE) between these states is absorbed, an electron in the molecule transitions to an excited state. This process is studied in electronic spectroscopy which focuses on the UV and visible spectrum to assess such electronic transitions.
The concept of quantized energy steps is crucial to understanding absorption. For a molecule to absorb a photon, there must be a precise match between the energy of the photon and the energy required to transition an electron to a higher orbital. In the context of visible light, photons within the energy range of 1.63 to 3.26 electron volts (eV) match the energy differences between the outer electron shells of many atoms and molecules, therefore they can be absorbed, promoting electrons to higher energy levels.
For instance, when visible light is absorbed by pigments in photosynthetic organisms, certain wavelengths (colors) of light are absorbed while others are reflected or transmitted, all dependent on the energy levels available for electrons to transition to within the pigment molecules.