Philippe F. Weck

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Citation Safavi-Naini, A. et al. " Microscopic model of electric-field-noise heating in ion traps. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits(More)
Phases of the iron-oxygen binary system are significant to most scientific disciplines, directly affecting planetary evolution, life, and technology. Iron oxides have unique electronic properties and strongly interact with the environment, particularly through redox reactions. The iron-oxygen phase diagram therefore has been among the most thoroughly(More)
Technetium dichloride has been discovered. It was synthesized from the elements and characterized by several physical techniques, including single crystal X-ray diffraction. In the solid state, technetium dichloride exhibits a new structure type consisting of infinite chains of face sharing [Tc(2)Cl(8)] rectangular prisms that are packed in a commensurate(More)
The structures and properties of layered technetium dichalcogenides TcX2 (X = S, Se, Te) have been investigated using density functional theory. The equilibrium structures of TcSe2 and TcTe2, adopting distorted Cd(OH)2-type unit cells similar to TcS2, are reported for the first time at the atomic level, along with their electronic properties. In contrast to(More)
We combine experimental observations with ab initio calculations to study the reversible hydrogenation of single-wall carbon nanotubes using high boiling polyamines as hydrogenation reagents. Our calculations characterize the nature of the adsorption bond and identify preferential adsorption geometries at different coverages. We find the barrier for(More)
The structures of the only known minerals containing peroxide, namely studtite [(UO(2))O(2)(H(2)O)(4)] and metastudtite [(UO(2))O(2)(H(2)O)(2)], have been investigated using density functional theory. The structure of metastudtite crystallizing in the orthorhombic space group Pnma (Z = 4) is reported for the first time at the atomic level and the computed(More)
A second polymorph of technetium dichloride, β-TcCl2, has been synthesized from the reaction of Tc metal and chlorine in a sealed tube at 450 °C. The crystallographic structure and physical properties of β-TcCl2 have been investigated. The structure of β-TcCl2 consists of infinite chains of face sharing [Tc2Cl8] units; within a chain, the Tc≡Tc vectors of(More)
Technetium trichloride has been synthesized by reaction of Tc(2)(O(2)CCH(3))(4)Cl(2) with HCl(g) at 300 °C. The mechanism of formation mimics the one described earlier in the literature for rhenium. Tc(2)(O(2)CCH(3))(2)Cl(4) [P1̅; a = 6.0303(12) Å, b = 6.5098(13) Å, c = 8.3072(16) Å, α = 112.082(2)°, β = 96.667(3)°, γ = 108.792(3)°; Tc-Tc = 2.150(1) Å] is(More)
The structure of β-molybdenum dichloride is compared with that of TcCl(2) using EXAFS spectroscopy. For TcCl(2), the Tc atom is surrounded by Tc atoms at 2.13(2), 3.45(3), 3.79(4), and 4.02(4) Å. For β-MoCl(2), the Mo is surrounded by Mo atoms at 2.21(2), 2.91(3), and 3.83(4) Å. The latter distances are consistent with the presence of an [Mo(4)Cl(12)] unit(More)
Trinuclear transition-metal complexes such as Re(3)X(9) (X = Cl, Br, I), with their uniquely featured structure among metal halides, have posed intriguing questions related to multicenter electron delocalization for several decades. Here we report a comprehensive study of the technetium halide clusters [Tc(3)(μ-X)(3)X(6)](0/1-/2-) (X = F, Cl, Br, I),(More)