Photoswitchable coordination compounds

t. Chirality and Chiral Homogeneity in Nature 2. Biotic Theories 3. Abiotic Theories 3.1. Chance Mechanisms 3.1.1. Models for Spontaneous Symmetry Breaking 3.1.2. Spontaneous Resolution on Crystallization 3.1.3.Asymmetric Syntheses in Chiral Crystals 3.1.4. Asymmetric Adsorption and Catalysis on Quartz 3.1.5.Asymmetric Adsorption and Polymerization on Clays 3.1.6. Conclusions 3.2. Determinate Mechanisms 3.2.1. Regional and/or Temporal Processes 3.2.1.1.Electric, Magnetic and Gravitational Fields 3.2.1.2.Circularly Polarized Eight 3.2.1.2.1.Asymmetric Photoequilibration 3.2.1.2.2.Photochemical Asymmetric Synthesis 3.2.1.2.3.Asymmetric Photolysis 3.2.1.2.4.Sources of Circularly Polarized Eight 3.2.2. Universal Processes 3.2.2.l.The Violation of Parity 3.2.2.2.The Vester-Ulbricht (V-U) ttypothesis 3.2.2.3.Radioracemization 3.2.2.4.Direct Effects of Chiral Particles 3.2.2.4.1 .Electrons 3.2.2.4.2.Protons 3.2.2.4.3.Positrons and Muons 3.2.2.5.Weak Interactions, Neutral Currents and Parity Violating Energy Differences 3.2.3. Conclusions 4. The Amplification of Enantiomeric Excesses

The origin and amplification of biomolecular chirality

The high-energy particle transport code NMTC/JAM, which has been developed at JAERI, was improved for the high-energy heavy ion transport calculation by incorporating the JQMD code, the SPAR code and the Shen formula. The new NMTC/JAM named PHITS (Particle and Heavy-Ion Transport code System) is the first general-purpose heavy ion transport Monte Carlo code over the incident energies from several MeV/nucleon to several GeV/nucleon.

https://www.tandfonline.com/doi/pdf/10.1080/18811248.2002.9715305

Development of General-Purpose Particle and Heavy Ion Transport Monte Carlo Code

In der Ubergangsmetallchemie gibt es eine Klasse von Komplexverbindungen, bei denen eine Temperaturerniedrigung einen Wechsel im Spinzustand des Zentralatoms vom High-Spin- in den Low-Spin-Zustand bewirkt. Dabei andern sich die magnetischen und optischen Eigenschaften, uber die der thermische Spinubergang (auch Spincrossover genannt) sehr gut verfolgt werden kann. Dieses Phanomen tritt sowohl in flussiger Phase als auch im Festkorper auf. Eine herausragende Stellung nehmen Eisen(II) - Spincrossover - Verbindungen ein, in denen der Spinubergang im Festkorper auf sehr unterschiedliche Weise - graduell, abrupt, mit Hysterese oder stufenweise - verlaufen kann und mit Mosbauer- und optischer Spektroskopie, mit magnetischen Suszeptibilitats- und Warmekapazitatsmessungen sowie durch Kristallstrukturanalyse intensiv untersucht worden ist. Die kooperative Wechselwirkung zwischen den einzelnen Komplexmolekulen kann befriedigend durch elastische Eigenschaften und durch die Anderung von Gestalt und Volumen der Komplexmolekule beim Spinubergang erklart werden. Bei Untersuchungen an Eisen(II)-Spincrossover-Verbindungen konnte man beobachten, das sich der Low-Spin-Zustand mit grunem Licht in den High-Spin-Zustand umschalten last, der bei tiefen Temperaturen eine nahezu unendlich lange Lebensdauer haben kann (LIESST = Light-Induced Excited Spin State Trapping). Mit rotem Licht last sich der metastabile High-Spin- wieder in den Low-Spin-Zustand zuruckschalten. Der Mechanismus des LIESST-Effekts ist aufgeklart, die Zerfallskinetik im Detail untersucht und im Rahmen der Theorie strahlungsloser Ubergange verstanden. Anwendungen des LIESST-Effekts in der optischen Informationstechnik sind denkbar.

Thermisch und optisch schaltbare Eisen(II)‐Komplexe

▪ Abstract Beam-based positron annihilation spectroscopy (PAS) is a powerful porosimetry technique with broad applicability in the characterization of nanoporous thin films, especially insulators. Pore sizes and distributions in the 0.3–30 nm range are nondestructively determined with only the implantation of low-energy positrons from a table-top beam. Depth-profiling with PAS has proven to be an ideal way to measure the interconnection length of pores, search for depth-dependent inhomogeneities or damage in the pore structure, and explore porosity hidden beneath dense layers or diffusion barriers. The capability of PAS is rapidly maturing as new intense positron beams around the globe spawn more accessible PAS facilities. After a short primer on the physics of positrons in insulators, the various probe techniques of PAS are briefly summarized, followed by a more detailed discussion of the wide range of nanoporous film parameters that PAS can characterize.

/pdf/positron-annihilation-as-a-method-to-characterize-porous-29acb2wfpx.pdf

Positron annihilation as a method to characterize porous materials

Magnetic hyperfine fields near the Fe / Cr (100, 110) interface studied by CEMS

A new spectrometer for time-differential Mossbauer spectroscopy was developed featuring high count rate capability, good time resolution, and flexible data handling.

A new spectrometer for Time-Differential Mössbauer Emission Spectroscopy (TDMES)

https://estudogeral.sib.uc.pt/bitstream/10316/4467/1/file6ee30997fd5b45f8a205f43718722f6a.pdf

Free-volume studies in polyurethane membranes by positron annihilation spectroscopy

A low-noise scintillation counter has been developed for the detection of low-intensity, low-energy (several keV) electrons in high vacuum. Performance comparisons with a channeltron for 57 Fe depth-selective conversion electron Mossbauer spectroscopy (DCEMS) show a substantial improvement in counting time in favour of the scintillation detector.

Improvements in 57Fe depth-selective conversion electron Mössbauer spectroscopy by applying a low-noise scintillation electron detector

A spectrometer has been constructed for depth selective conversion electron Mossbauer spectroscopy using an electrostatic cylindrical mirror analyzer. The spectrometer allows depth selective investigations even of samples with 57Fe in natural abundance. This was demonstrated on an Fe78B11Si9C2 amorphous metglas where the magnetic hyperfine field and the orientation of the magnetization was determined in dependence of the distance from the sample surface.

Zs. Kajcsos

Papers

Magnetic hyperfine fields near the Fe / Cr (100, 110) interface studied by CEMS

A new spectrometer for Time-Differential Mössbauer Emission Spectroscopy (TDMES)

Free-volume studies in polyurethane membranes by positron annihilation spectroscopy

Improvements in 57Fe depth-selective conversion electron Mössbauer spectroscopy by applying a low-noise scintillation electron detector

An electron spectrometer for depth selective conversion electron Mössbauer spectroscopy