[Widdekind]

Reportedly,

Quote

at low temperatures, molecules seem to increase their apparent surface area for interaction with light

So, as molecules cool down, and "vibrate less", they "settle into" some stable cold condition, wherewithin they are "more receptive" to incident light ?? If so, then conversely, as molecules heat up, they "vibrate more", and their wave-functions "blur", "smearing out" in momentum-and-energy. Does that mean, that at higher temperatures, wave-functions are "constantly perturbed" into "blurred semi-excited states", which become only "partially present", at any single given "mono-chromatic" energy/frequency ?? Is that why high-T molecules "see less of the light" incident upon them, i.e. the molecules become "energetically blurred" and "detuned" from any given incident frequency of light ??

[swansont]

No, this really has nothing to do with the wave function.

From the look of it this is no more than reducing the Doppler-broadening of the absorption; you cool the molecule and it has a better chance of being in resonance with the laser, increasing the cross-section, i.e. the absorption probability. The frequency shift due to motion is kv (k is the wave vector, and it's actually a dot product), so reducing the temperature by a factor of order 100 means a reduction of 10,000 in the width of the transition.