2,147 research outputs found
Trichlorido{2-[2-(η5-cyclopentadienyl)-2-methylpropyl]-1-trimethylsilyl-1H-imidazole-κN 3}titanium(IV) tetrahydrofuran hemisolvate
The title compound, [Ti(C15H23N2Si)Cl3]·0.5C4H8O, has been prepared from {2-[2-(η5-cyclopentadienyl)-2-methylpropyl]-1H-imidazolyl-κN
1}bis(N,N-diethylamido-κN)titanium(IV), (C12H14N2)Ti(NEt2)2, by reaction with excess of Me3SiCl in tetrahydrofuran (THF) at 353 K. The crystal structure contains THF as adduct solvent, disordered around a center of inversion. The presence of THF and the adduct ratio has been independently supported by 1H NMR spectroscopy. The coordination polyhedron of the Ti atom is distorted square-pyramidal, assuming the cyclopentadienyl (Cp) ring occupies one coordination site. The Ti, Si and CH2 group C atoms only deviate slightly from the imidazole ring plane [by 0.021 (4), 0.133 (4) and 0.094 (4) Å, respectively]. Comparison of the principal geometric parameters with those of the few known structurally characterized analogues reveal small differences in bond lengths and angles at the Ti atom. The title complex is only stable in THF-d
8 in the presence of excess Me3SiCl, otherwise it exists in an equilibrium with equimolar amounts of dichlorido{2-[2-(η5-cyclopentadienyl)-2-methylpropyl]-1H-imidazolyl-κN
3}titanium(IV) and chlorotrimethylsilane
On "the authentic damping mechanism" of the phonon damping model
Some general features of the phonon damping model are presented. It is
concluded that the fits performed within this model have no physical content
Two-phonon 1- state in 112Sn observed in resonant photon scattering
Results of a photon scattering experiment on 112Sn using bremsstrahlung with
an endpoint energy of E_0 = 3.8 MeV are reported. A J = 1 state at E_x =
3434(1) keV has been excited. Its decay width into the ground state amounts to
Gamma_0 = 151(17) meV, making it a candidate for a [2+ x 3-]1- two-phonon
state. The results for 112Sn are compared with quasiparticle-phonon model
calculations as well as the systematics of the lowest-lying 1- states
established in other even-mass tin isotopes. Contrary to findings in the
heavier stable even-mass Sn isotopes, no 2+ states between 2 and 3.5 MeV
excitation energy have been detected in the present experiment.Comment: 10 pages, including 2 figures, Phys. Rev. C, in pres
One-neutron knockout from Ni
The single-particle structure of Ni and level structure of Ni
were investigated with the \mbox{Be (Ni,Ni+)} reaction at 73 MeV/nucleon. An inclusive cross
section of 41.4(12) mb was obtained for the reaction, compared to a theoretical
prediction of 85.4 mb, hence only 48(2)% of the theoretical cross section is
exhausted. This reduction in the observed spectroscopic strength is consistent
with that found for lighter well-bound nuclei. One-neutron removal
spectroscopic factors of 0.58(11) to the ground state and 3.7(2) to all excited
states of Ni were deduced.Comment: Phys. Rev. C, accepte
Small Corrections to the Tunneling Phase Time Formulation
After reexamining the above barrier diffusion problem where we notice that
the wave packet collision implies the existence of {\em multiple} reflected and
transmitted wave packets, we analyze the way of obtaining phase times for
tunneling/reflecting particles in a particular colliding configuration where
the idea of multiple peak decomposition is recovered. To partially overcome the
analytical incongruities which frequently rise up when the stationary phase
method is adopted for computing the (tunneling) phase time expressions, we
present a theoretical exercise involving a symmetrical collision between two
identical wave packets and a unidimensional squared potential barrier where the
scattered wave packets can be recomposed by summing the amplitudes of
simultaneously reflected and transmitted wave components so that the conditions
for applying the stationary phase principle are totally recovered. Lessons
concerning the use of the stationary phase method are drawn.Comment: 14 pages, 3 figure
P16-32. Antigen exposure regulates the balance between proliferating and cytotoxic subsets of virus-specific CD8 T-cells
Tunneling Violates Special Relativity
Experiments with evanescent modes and tunneling particles have shown that i)
their signal velocity may be faster than light, ii) they are described by
virtual particles, iii) they are nonlocal and act at a distance, iv)
experimental tunneling data of phonons, photons, and electrons display a
universal scattering time at the tunneling barrier front, and v) the properties
of evanescent, i.e. tunneling modes is not compatible with the special theory
of relativity
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