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Chemistry · Physics
Molecules and light
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Send a photon toward a molecule. Observe transmission and absorption in three dimensions.
CO₂. Linear · 1 C and 2 O · O–C–O angle = 180°. Ready for a photon. Select “Send one photon” and watch what happens when it reaches the molecule. Drag to orbit. Close-up focuses on the molecule; reset the view to see the entire photon path. Colors, sizes and times are illustrative.
Preparing the 3D scene…
CO₂
Infrared
Ready for a photon
CO₂ · Carbon dioxide
Linear · 1 C and 2 O · O–C–O angle = 180°
Selected vibrational bands
Display and speed
Symbolic interface tones, not molecular sound or radiation frequency.
Keyboard: Tab moves between controls; Enter/Space activates. Arrows choose a molecule/source; Alt+K plays/pauses; Alt+L steps when paused.
Ready for a photon
Select “Send one photon” and watch what happens when it reaches the molecule.
Photon energy increases →
Explore the electromagnetic spectrum
Reference spectrum · does not change the source illuminating the molecule.
λ decreases → · f and E increase →
Visible
- λ
- 5.5E-7 m
- f
- 5.45E14 Hz
- E
- 2.25E0 eV
c = λf · E = hf
Conventional boundaries: visible 400–700 nm; UV 10–400 nm. Microwaves belong to the radio family; X-rays/gamma rays also differ by origin. This spectrum does not predict sample absorption.
Keep the radiation and change the molecule — does it respond the same way?
Model notes
- Photons represent selected rotational transitions and vibrational bands. Actual absorption depends on wavelength and molecular state; not every photon in a spectral region is absorbed.
- Visible light represents the green region near 550 nm; ultraviolet represents UV-B near 300 nm. O₂ can dissociate at shorter UV wavelengths. Weak visible absorption by O₃ and magnetic-dipole microwave absorption by O₂ are omitted.
- Colors outside the visible region, wave packets, sizes, times and motion amplitudes are illustrative. A photon is not a ball colliding with a molecule. The surrounding glow only indicates an excited state.
- The model selects a radiative relaxation channel; collisions and other processes can also transfer energy. Combined motions, detailed spectra and electronic states of dissociation fragments are omitted.
- Each exposure considers one photon and one molecule in its initial state. Repeat mode replaces the sample between exposures; fragments are not shown spontaneously recombining.
- The reference electromagnetic spectrum uses λf=c and E=hf in vacuum; region boundaries are conventional, not the sample's absorption spectrum. The spectrum slider does not change the illuminating radiation. Optional sounds are interface cues only.