Generating CaF Molecules for LIBS and LAMIS Analysis

As part of Spectroscopy’s coverage of the Winter Conference on Plasma Spectrochemistry, which took place in Tucson, Arizona, from January 9^th–17^th, we sat down with Martin Resano, a Coordinator of the Rapid Analysis Methods with Spectroscopic Techniques (MARTE) group and as part of the Aragon Institute for Engineering Research (I3A) at the University of Zaragoza (Spain), to talk about the challenges and advancements in obtaining isotopic information using atomic spectroscopy (1,2).

Spectroscopy: A recent study of yours introduced a new way to generate CaF molecules in the gaseous phase for laser induced breakdown spectroscopy (LIBS) and laser ablation molecular isotopic spectroscopy (LAMIS) analysis. What motivated the decision to add the molecule-forming reagent directly into the plasma plume, and what advantages does this approach offer compared to traditional molecular generation methods?

Martin Resano: The rationale behind that is that when you want to obtain isotopic information, atomic spectroscopy is difficult because the isotopic shifts that you're going to see are very small, but if you form molecules, the shifts are much larger. So, if you want to see differences in the isotopes of calcium, it’s easier if we form a molecule with calcium, with something else, in this case, fluorine. So, normally, the traditional procedure for doing that is that when you shoot your sample, you vaporize it, and then you have a lot of atoms and ions because it's very hot. And then with time, the temperature drops, and you have molecule formation. Then, you may have your calcium fluorine molecule, but these are at different times. First, you have ions and atoms, and then you have the molecules. By adding the fluorinated agent in the gaseous phase, you can have this molecule form at the same time when it's still hot, and you have ions and elements. So, you can obtain information about calcium, fluorine, a molecule, and at the same time, you can look at other elements that will be in the form of atoms.

Spectroscopy: Because the technique provides access to both elemental concentration and isotopic composition, it opens the door to new LIBS applications such as tracer studies. What future research directions or real-world problems do you envision this dual-capability approach helping to address?

Martin Resano: The work actually is more proof-of-concept of what we can do. I think that it's a clear advantage to be able to measure molecules and ions at the same time, but we need to further improvement because, for instance, metal fluoride reacts very well with calcium, but it doesn't react with other elements. We need to look for a different bunch of gasses to create other molecules. Another problem that we have with our system right now is that the repetition rate is quite low. It's only up to 20 shots per second, and that affects the sensitivity. With other laser systems that we have that are capable of shooting 1000 times per second, the sensitivity will be much better, and then we will have possibilities to find a wider range of applications.

This video clip is the second part of our conversation with Resano. To stay up to date on our coverage of the Winter Conference, click here.

References

1. Wetzel, W. Inside the Laboratory: The MARTE Group at the University of Zaragoza. Spectroscopy. Available at: (accessed 2026-01-20).
2. IASA, Winter Conference on Plasma Spectrochemistry. IASA. Available at: https://iasa.world/winter-plasma-conference (accessed 2026-01-19).