The Sounds of Atoms

 January 09 2023

Finding patterns in the electrical structures of atoms is made enjoyable by converting the spectral lines of each element into musical tones.

(Top) Hydrogen's visible spectrum is made up of a number of emission lines. These lines come together to create the distinctive magenta hue when hydrogen gas is agitated. (Right bottom) Researchers can produce a trademark sound or waveform that is exclusive to this element by turning these similar lines into sounds and merging them with audio software.

Jill Linz sought to combine her experience with classical music with her work as a physics educator at Skidmore College in New York early on in her career. A project that translated atomic data into distinctive aural tones provided her with a platform for this interdisciplinary collaboration. She has since completed a "aural periodic table" using what was originally intended to be an instructional tool. She is starting to investigate how this "sonification" of atoms can reveal surprising structural linkages among elements by evaluating the waveforms and tonal properties of each element in the table. The project was presented at the Acoustical Society of America's 183rd Meeting.

In 1997, Linz was inspired to start sonifying atoms while instructing a class on digital synthesis methods and musical acoustics. She exclaims, "I wanted to produce nice noises." And she succeeded in doing so by creating waves that resembled the spectral lines of carbon, hydrogen, and other basic elements. These spectral lines represent changes in the electronic energy levels that cause light to emit at particular frequencies. Linz converted these visible frequencies to audible frequencies on a scale of 0 to 1000 Hz. She then entered the converted frequencies and the relative amplitudes—a quantity that represented the brightness of that colour component—into a digital audio application, which mixed them to create a basic raw sound. In the end, she produced a tone that sounds more agreeable to the ear by adding an exponential decay to this sound. These unique atom tones served as the basis for classical and modern musical compositions, with scientific investigation being a distant notion.

However, Linz placed a premium on accuracy as a physicist and educator. Linz's physics and chemistry coworkers prompted her to publish her techniques and finish a whole periodic table as the Atom Music project grew and became a well-liked course among both science and nonscience students. For blind pupils who couldn't see charts or spectral lines, the initial concept came from chemistry, according to the author. She only produced tones for the eight basic elements at the moment, but in 2016 she made the decision to produce tones for every element in the periodic table. It proved to be considerably harder than I had anticipated to ensure the science was accurate and see it through.

the first 12 elements' waveforms. Hydrogen, helium, lithium, and beryllium are displayed in the left column, followed by boron, carbon, nitrogen, and oxygen in the centre column, then fluorine, neon, sodium, and magnesium in the right column, from top to bottom. Here, you may hear the sound of every particle.

Linz and a research assistant studied the spectral lines that have been detected for each element using information from the National Institute of Standards and Technology. According to Linz, who points out that some pieces contain hundreds of intertwining lines, there is no mathematical technique to automate this. To decide which lines were crucial for producing a sound and which were not, she had to design an algorithm. She then employed signal-processing techniques to produce sounds from the arithmetic total of each pair of lines using audio engineering software.

The audible periodic table was ultimately finished by Linz by November 2022. If any of the periodic table groups—metals, noble gases, or alkalines—could be distinguished by their sounds, her chemical peers were immediately interested. Do all elements, such as those in the transition metal group, have the same tonal characteristics? "We noticed certain relationships between the waveforms of various components. However, no periodic table categories were supported by these relationships, according to Linz. On how outer shell electrons can be shared by atoms to create chemical bonds, periodic table groupings are founded. However, the transitions that electrons perform within a single atom constitute the foundation for spectral lines. The fact that periodic table groupings did not exhibit the same patterns as sounds produced by spectral lines makes sense, according to Linz.

With this sample of atom tones, low-mass and high-mass elements are contrasted. Noble gases (He), nonmetals (C, N, O), halogens (F, Cl, Br), and metals are among the several groupings that are represented (Au, Hg, Th, Pb).

Instead, by organising the pieces into groups based on how harmonic they sound, Linz and her colleagues are investigating what patterns emerge. Lower mass elements, including carbon, oxygen, and hydrogen, frequently produce discordant tones, according to a pattern they have so far discovered. The spectral lines of these light elements are distributed throughout the full spectrum. Lead, a heavier metal, has purer tones that are often higher pitched. The spectral lines of these components are significantly closer together, leading to a waveform that resembles a pure sine wave. Thallium, however, is an outlier among the heavy metals because of its exceptionally discordant sound. It's out of place. This kind of anomalous trend interests me, says Linz.

She intends to investigate links between waveform type and quality more thoroughly in the future. Are there any components that have a high-pitched sinusoidal sound in common? Or ones that are jarring and dissonant? Can we learn anything about the internal structure of the atom from these patterns? A sound engineer listens not just to the tone but also to the spectral distribution and digital waveform. Perhaps physicists and chemists with an interest in music might do the same to learn more about the atomic elements.

The auditory periodic table is demonstrating its appeal to both science and music. Numerous musical endeavours have previously been influenced by atom sounds, including a blues song created using the "chords" of the helium atom and a composition of "water" music created by combining the notes from the hydrogen and oxygen spectra. Upcoming concerts feature the string orchestra's Atomic Suite and a composition based on the tonalities of iron and oxygen, two essential elements of red blood cell transmission. The atom music was hailed as "amazing" by attendees of the Acoustical Society of America's winter meeting, and they approached Linz about collaborating on both music synthesis and physics research. "I think what I've made is a new instrument to see into the atomic world," she explains. I sincerely hope that it proves to be helpful to others as well.

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