Recent Approaches for Chemical Speciation and Analysis by Electrospray Ionization (ESI) Mass Spectrometry

In recent years, the chemical speciation of several species has been increasingly monitored and investigated, employing electrospray ionization mass spectrometry (ESI-MS). This soft ionization technique gently desolvates weak metal\u2013ligand complexes, taking them in the high vacuum sectors of mass spectrometric instrumentation. It is, thus, possible to collect information on their structure, energetics, and fragmentation pathways. For this reason, this technique is frequently chosen in a synergistic approach to investigate competitive ligand exchange-adsorption otherwise analyzed by cathodic stripping voltammetry (CLE-ACSV). ESI-MS analyses require a careful experimental design as measurement may face instrumental artifacts such as ESI adduct formation, fragmentation, and sometimes reduction reactions. Furthermore, ESI source differences of ionization efficiencies among the detected species can be misleading. In this mini-review are collected and critically reported the most recent approaches adopted to mitigate or eliminate these limitations and to show the potential of this analytical technique

QED self-energy contribution to highly-excited atomic states

We present numerical values for the self-energy shifts predicted by QED (Quantum Electrodynamics) for hydrogenlike ions (nuclear charge $60 \le Z \le 110$) with an electron in an $n=3$, 4 or 5 level with high angular momentum ($5/2\le j \le 9/2$). Applications include predictions of precision transition energies and studies of the outer-shell structure of atoms and ions.Comment: 20 pages, 5 figure

Relativistic Calculation of two-Electron one-Photon and Hypersatellite Transition Energies for 12≤Z≤3012\leq Z\leq30 Elements

Energies of two-electron one-photon transitions from initial double K-hole states were computed using the Dirac-Fock model. The transition energies of competing processes, the K$\alpha$ hypersatellites, were also computed. The results are compared to experiment and to other theoretical calculations.Comment: accepted versio

Incorporation Of Broadband Access Technology In A Telecommunications Engineering Technology Program

The so-called “last mile” of the telecommunications network, which links residences and business locations to the network, has traditionally been the last bastion of old technology. Residential voice service is still mostly provided via an analog signal over a pair of copper wires that connects the telephone to a switching system in a central office. The high-speed digital technology employed by modern switching systems and inter-office transmission systems does not extend to most residences. The local access network is a landscape of copper wires bound into large cables, splices, cross-boxes and other equipment that has provided voice-grade service over the years. However, the landscape is changing dramatically as both residential and business customers demand more and more bandwidth for a growing number of services including high-speed Internet access and video as well as voice. Telcos such as AT&T and Verizon as well as Multi-Service Operators (MSOs) are both vying to provide the “triple play” (voice, data and video) to these customers. In order to provide the triple play, service providers are introducing digital transmission and optical fiber, which have revolutionized long-haul communication, to the local access network. The Telecommunication Engineering Technology program at RIT is responding to this trend by providing courses and laboratory facilities to introduce students to the associated technology. Our Telecommunication Systems Laboratory now features both passive optical network (PON) and hybrid fiber/coax (HFC) technology. These are two leading approaches to provide broadband access to support the triple play. In addition, we are developing new courses to cover topics such as video transmission and broadband network engineering. This paper presents the current status of our laboratory and course development along with our plans for future enhancements

The Electrostatic Ion Beam Trap : a mass spectrometer of infinite mass range

We study the ions dynamics inside an Electrostatic Ion Beam Trap (EIBT) and show that the stability of the trapping is ruled by a Hill's equation. This unexpectedly demonstrates that an EIBT, in the reference frame of the ions works very similar to a quadrupole trap. The parallelism between these two kinds of traps is illustrated by comparing experimental and theoretical stability diagrams of the EIBT. The main difference with quadrupole traps is that the stability depends only on the ratio of the acceleration and trapping electrostatic potentials, not on the mass nor the charge of the ions. All kinds of ions can be trapped simultaneously and since parametric resonances are proportional to the square root of the charge/mass ratio the EIBT can be used as a mass spectrometer of infinite mass range

Effects of Fe doping in La1/2Ca1/2MnO3

The effect of Fe doping in the Mn site on the magnetic, transport and structural properties of polycrystalline La1/2Ca1/2MnO3 was studied. Doping with low Fe concentration (< 10%) strongly affects electrical transport and magnetization. Long range charge order is disrupted even for the lowest doping level studied (~2%). For Fe concentration up to 5% a ferromagnetic state develops at low temperature with metallic like conduction and thermal hysteresis. In this range, the Curie temperature decreases monotonously as a function of Fe doping. Insulating behavior and a sudden depression of the ferromagnetic state is observed by further Fe doping.Comment: 2 pages, presented at ICM2000, to appear in JMM

Do electrospray mass spectra of surfactants mirror their aggregation state in solution?

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Evaluation of the self-energy correction to the g-factor of S states in H-like ions

A detailed description of the numerical procedure is presented for the evaluation of the one-loop self-energy correction to the $g$-factor of an electron in the $1s$ and $2s$ states in H-like ions to all orders in $Z\alpha$.Comment: Final version, December 30, 200

X-Ray Transitions from Antiprotonic Noble Gases

The onset of antiprotonic X-ray transitions at high principal quantum numbers and the occurence of electronic X-rays in antiprotonic argon, krypton, and xenon has been analyzed with the help of Multiconfiguration Dirac-Fock calculations. The shell-by-shell ionisation by Auger electron emission, characterised by appearance and disappearance of X-ray lines, is followed through the antiprotonic cascade by considering transition and binding energies of both the antiproton and the remaining electrons. Electronic lines could be attributed partly to specific states of the antiprotonic atom de-excitation.Comment: 16 pages, 13 figure