Quantum Emulation of Extreme Non‐Equilibrium Phenomena with Trapped Atoms

Ultracold atomic physics experiments offer a nearly ideal context for the investigation of quantum systems far from equilibrium. We describe three related emerging directions of research into extreme non‐equilibrium phenomena in atom traps: quantum emulation of ultrafast atom‐light interactions, coherent phasonic spectroscopy in tunable quasicrystals, and realization of Floquet matter in strongly‐driven lattice systems. We show that all three should enable quantum emulation in parameter regimes inaccessible in solid‐state experiments, facilitating a complementary approach to open problems in non‐equilibrium condensed matter.     

Overtone mobility spectrometry: Part 2. Theoretical considerations of resolving power

The transport of ions through multiple drift regions is modeled to develop an equation that is useful for an understanding of the resolving power of an overtone mobility spectrometry (OMS) technique. It is found that resolving power is influenced by a number of experimental variables, including those that define ion mobility spectrometry (IMS) resolving power: drift field (E), drift region length (L), and buffer gas temperature (T). However, unlike IMS, the resolving power of OMS is also influenced by the number of drift regions (n), harmonic frequency value (m), and the phase number (Φ) of the applied drift field. The OMS resolving power dependence upon the new OMS variables (n, m, and Φ) scales differently than the square root dependence of the E, L, and T variables in IMS. The results provide insight about optimal instrumental design and operation.     

Overtone mobility spectrometry: Part 1. Experimental observations

A new method that allows a linear drift tube to be operated as a continuous ion mobility filter is described. Unlike conventional ion mobility instruments that use an electrostatic gate to introduce a packet of ions into a drift region, the present approach uses multiple segmented drift regions with modulated drift fields to produce conditions that allow only ions with appropriate mobilities to pass through the instrument. In this way, the instrument acts as a mobility filter for continuous ion sources. By changing the frequency of the applied drift fields it is possible to tune this instrument to transmit ions having different mobilities. A scan over a wide range of drift field frequencies for a single ion species shows a peak corresponding to the expected resonance time of the ions in one drift region segment and a series of peaks at higher frequencies that are overtones of the resonant frequency. The measured resolving power increases for higher overtones, making it possible to resolve structures that were unresolved in the region of the fundamental frequency. We demonstrate the approach by examining oligosaccharide isomers, raffinose and melezitose as well as a mixture of peptides obtained from enzymatic digestion of myoglobin.     

Overtone Mobility Spectrometry: Part 3. On the Origin of Peaks

The origin of non-integer overtone peaks in overtone mobility spectrometry (OMS) spectra is investigated by ion trajectory simulations. Simulations indicate that these OMS features arise from higher-order overtone series. An empirically-derived formula is presented as a means of describing the positions of peaks. The new equation makes it possible to determine collision cross sections from any OMS peak. Additionally, it is extended as a means of predicting the resolving power for any peak in an OMS distribution.     

Low temperature solventless synthesis and characterization of Ni and Fe magnetic nanoparticles

We have successfully implemented a facile, one-pot solventless synthesis procedure starting from acetylacetonate salts and CaH(2) to obtain carbon-coated ferromagnetic metallic Ni and Fe nanoparticles at low temperature. The use of CaH(2) as a reductant drastically reduces reaction temperature down to 140 °C.     

Overtone Mobility Spectrometry: Part 4. OMS-OMS Analyses of Complex Mixtures

A new, two-dimensional overtone mobility spectrometry (OMS-OMS) instrument is described for the analysis of complex peptide mixtures. OMS separations are based on the differences in mobilities of ions in the gas phase. The method utilizes multiple drift regions with modulated drift fields such that only ions with appropriate mobilities are transmitted to the detector. Here we describe a hybrid OMS-OMS combination that utilizes two independently operated OMS regions that are separated by an ion activation region. Mobility-selected ions from the first OMS region are exposed to energizing collisions and may undergo structural transitions before entering the second OMS region. This method generates additional peak capacity and allows for higher selectivity compared with the one-dimensional OMS method. We demonstrate the approach using a three-protein tryptic digest spiked with the peptide Substance P. The [M + 3H]³⁺ ion from Substance P can be completely isolated from other components in this complex mixture prior to introduction into the mass spectrometer.     

Improved Hiyama cross-coupling reactions using HOMSi® reagents: a novel application of a palladacycle

Various parameters in the Hiyama cross-coupling reaction of HOMSi® reagents with ethyl bromobenzoate were studied. These included solvent, ligand, palladium source, and added water. DMF and THF were found to be excellent solvents. Palladium chloride was found to be the best palladium source and no added water was required. The use of tri-o-tolylphosphine as the ligand proved to be particularly effective.     

Direct patterning of nanostructured ceramics from solution—differences from conventional printing and lithographic methods

We have proposed an innovative concept and technology, “soft processing” or “soft solution processing,” which aims at low energetic (environmentally benign) fabrication of shaped, sized, located, and oriented ceramic materials by chemical reactions in or from solutions. By activating or stimulating those reactions locally and/or moving the reaction point dynamically, we can obtain patterned ceramic films directly in solution without any postheating, masking, or etching. Using those “direct patterning” concepts and technologies, we have developed methods for direct patterning of CdS, PbS, and CaWO₄ on paper substrates by ink-jet reaction at RT and TiO₂ patterning on a glass substrate by ink-jet deposition at <573 K. Furthermore, we have succeeded in fabricating a BaTiO₃ pattern by a laser beam-assisted process and a carbon pattern by a needle electrode, directly in solutions at ambient temperatures and pressures.