Rare Germanium Isotope Infrared Spectral Signatures Elucidated in Detail for the First Time

The press service of the Russian Ministry of Education and Science reported on August 25 that scientists from Tomsk Polytechnic University, in collaboration with an international research team, have for the first time conducted a detailed study of the infrared spectra of two rare germanium isotopes and identified characteristic spectral signatures that can be used to recognize the relevant isotopes in complex gas mixtures.

The research team selected two highly enriched isotopes—germanium-72 and germanium-73—as the subjects of the study, recording their spectral information using a high-resolution Fourier transform spectrometer. This instrument is capable of resolving closely spaced spectral lines, providing the conditions for analyzing subtle spectral changes induced by isotopic substitution.

The researchers stated that precise spectral data for different germanium isotopes remain relatively scarce in the scientific literature, and such data are of significant importance for identifying molecules in planetary atmospheres and for producing ultra-pure germanium isotopes for quantum technologies and modern electronics.

In principle, when one isotope is replaced by another, the mass of the molecule changes, which in turn affects its vibrational and rotational frequencies. This change is reflected in the infrared spectral "fingerprint" of the substance, enabling researchers to distinguish between different isotopic variants.

The project researchers noted that the team not only obtained individual measurement data but also established a reliable, high-precision model describing the interactions between different states of germanium isotopes. This model can help interpret known spectral lines and calculate lines for which experimental data are still incomplete.

To process the large volume of experimental data, the scientists employed a mathematical model developed at Tomsk Polytechnic University, integrating thousands of spectral transitions of the two types of studied molecules into a unified physical picture, thereby analyzing the effects of isotopic substitution on spectral properties.

Institutions participating in this study include Tomsk Polytechnic University, the Institute of High-Purity Chemistry of the Russian Academy of Sciences, the Institute of Applied Physics of the Russian Academy of Sciences, and Heilongjiang University in Harbin. The research was funded by the Ministry of Education and Science of the Russian Federation, and the results have been published in the Journal of Quantitative Spectroscopy and Radiative Transfer.