NOVA

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Speaker

So the story is bonds. Atomic bonds. But the thing to remember is that, in the atomic world, everything is in motion, vibrating because of thermal energy, heat. And that includes the bonds between atoms They're more like springs, oscillating. And according to a University of California at Riverside scientist, Ruoxue Yan, all that atomic vibration plays a specific tune shaped by the atoms and the bonds between them. The Song of the Molecule. (piano riff) So what do you mean when you talk about the Song of the Molecule? So we've all seen the "stick and ball" model of molecules in science class, right? They tell you what the molecules look like, how the atoms are arranged in the molecule, but what it didn't show is, the atoms in the molecules, they're not stationary. They're constantly moving. They can stretch, they can bend. And those vibrations make sounds, But they're actual notes? (stutters) I mean, obviously not this high, but-- (wheezing) -

Woman

Way, way over there, yes. But it's real-- -

Woman

Yeah. So it's like, when you play a high note, you will see it's always associated with the strings, that they're both short and thin. Right. These short, thin ones make... (piano plays) It's the same thing in molecular vibrations. So if the two atoms make up the bond are light, then like oxygen and hydrogen, then they move very violently, very quickly. So they give out high-pitched sound. So lighter things would be higher notes? Yes. Higher frequency. Alright. So like... Hydrogen! Yes, but hydrogen molecules, not element. Molecules! Nitrogen, oxygen Molecules! -

Woman

Exactly. Okay. What are some middle range ones? Like, alumina. Alumina! Titania. Titania! And silica. Silica! Okay and then, what's a low one? Like, silver oxide. Silver oxide Lead oxide. Lead oxide Radium permanganate. Radium permanganate! -

Man

Song of the Molecules by Ruoxue Yan and David Pogue. -

Speaker

The Song of the Molecules isn't a metaphor. In her lab, Ruoxue uses the vibrations of atoms and their bonds to identify a molecule's structure. She isn't the first to use the technique but she and her team have developed an inexpensive and portable way to detect the faint signals. It uses light sent down a glass optical fiber which gradually narrows. At the fiber's end, a silver nanowire focuses the light even more until it reaches the tip where it's just a few nanometers across about the width of a DNA molecule. The light it emits interacts with the vibrating target molecule revealing its structure. Here, Ruoxue has used the system to analyze carbon nanotubes that are made of a single sheet of carbon atoms rolled up into a cylinder. This is the tip of the device scanning across the surface. And once you heat the carbon nanotube, you'll certainly see these peaks, strong peaks coming up. -

Speaker

The tallest peak represents the atomic vibration perpendicular to the length of the carbon nanotube. All of the carbon atoms are going up and down, up and down. And you go here at a higher frequency, what happens is all of the carbon molecules are going left and right, left and right. That's a different motion and have different frequency. -

Speaker

Ruoxue thinks her system will give more labs around the world, a chance to examine the atomic structure of molecules in the kind of detail that has been limited to expensive facilities. Those vibrations, those sounds are too faint. They're very weak. So the secret to hear those whispers is to shine lights on them. Because light can turn them on and their voices can be enlarged light to several orders of magnitude so that you can actually hear them.