Design and Performance of an Acoustic Levitator System Coupled with a Tunable Monochromatic Light Source and a Raman Spectrometer for In Situ Reaction Monitoring

Abstract

The design and performance of a custom-built reaction chamber combined with an acoustic levitator, a tunable monochromatic light source, and a Raman spectrometer are reported. The pressure-compatible reaction chamber was vacuum-tested and coupled with the acoustic levitator that allows contactless sample handling, free of contingent sample requirements such as charge and refractive index. The calibration and performance of the Raman spectrometer was studied utilizing gated detection and three different gratings that can be interchanged within seconds for a desired resolution and photon collection range. A wide range of 186–5000 cm –1 Raman shift, with a small uncertainty of ±2 cm –1 , can be recorded covering a complete vibrational range in chemical reaction monitoring. The gating of the detector allowed operation under the room light and filtration of unwanted sample fluorescence. The in situ reaction perturbation and monitoring of physical and chemical changes of samples by the Raman system were demonstrated by degradation of polystyrene by monochromatic UV light and photobleaching of a potato slice by visible light. This instrument provides a versatile platform for in situ investigation of surface reactions, without external support structures and under controlled pressure and radiation conditions, relevant to various disciplines such as materials science, astrochemistry, and molecular biology.

Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment

“…Let us mention several examples of such ongoing work. Atomic and molecular clusters have been used to study single-particle and collective irradiation-driven phenomena. These systems enable elucidation of the role of the environment in the elementary quantum processes involved, the emergence of the collective response of the system upon its irradiation, and the evolution of the system properties from atomic toward bulk. Experimental studies are being conducted for isolated aerosols, liquid droplets, and liquid jets − , using acoustic , and optical levitation systems. Within the condensed-matter field, the liquid phase remains the least studied, and the transition of physical and chemical properties across the phases requires characterization.…”

“…Experimental studies are being conducted for isolated aerosols, liquid droplets, and liquid jets − , using acoustic , and optical levitation systems. Within the condensed-matter field, the liquid phase remains the least studied, and the transition of physical and chemical properties across the phases requires characterization.…”

In situ studies on free-standing synthesis of nanocatalysts via acoustic levitation coupled with pulsed laser irradiation

“…Acoustic levitation is suitable for a wide range of substances and is not restricted to any particular sample or shape. The major benefits of such a levitation process lie in eliminating the complicated impacts caused by the contacting wall or surface on the sample [4] . The contact between the chemical agent and container in the normal wet chemistry route triggers heterogeneous nucleation.…”

“…Moreover, acoustic levitation is increasingly attracting attention in the space research community for low-gravity simulation testing. The capability to levitate droplets or particles with a certain gas medium delivers ideal free-standing environments for simulating planetary dust particles and micrometeoroids present in the atmospheres of exoplanets and planets [4] , [7] .…”

In-situ monitoring of thiazine molecular aggregation in various solvents via a free-standing acoustic levitator

“…Furthermore, the levitator technique can be applied to a wide range of materials, including powders, solvents. Another significant aspect of the levitator droplet technique, which involves microliter quantities, is its propensity to facilitate complete reactions, thereby maximizing yield [25] , [26] , [27] , [28] .…”