4 research outputs found
On Spin Dependence of Relativistic Acoustic Geometry
This work makes the first ever attempt to understand the influence of the
black hole background space-time in determining the fundamental properties of
the embedded relativistic acoustic geometry. To accomplish such task, the role
of the spin angular momentum of the astrophysical black hole (the Kerr
parameter -- a representative feature of the background black hole metric)
in estimating the value of the acoustic surface gravity (the representative
feature of the corresponding analogue space time) has been investigated for
axially symmetric inflow of hydrodynamic fluid onto a rotating black hole.
Since almost all astrophysical black holes are supposed to posses some degree
of intrinsic rotation, the influence of the Kerr parameter on classical
analogue models is very important to understand.
For certain values of the initial boundary conditions describing the
aforementioned flow, more than one acoustic horizons, namely two black hole
type and one white hole type, may form, where the surface gravity may become
formally infinite at the acoustic white hole. The connection between the
corresponding analogue Hawking temperature with astrophysically relevant
observables associated with the spectral signature has been discussed.Comment: 22 pages, 11 figures, Comments welcom
Air oxygenation chemistry of 4-TBC catalyzed by chloro bridged dinuclear copper(ii) complexes of pyrazole based tridentate ligands: synthesis, structure, magnetic and computational studies.
Four dinuclear bis(μ-Cl) bridged copper(ii) complexes, [Cu(2)(μ-Cl)(2)(L(X))(2)](ClO(4))(2) (L(X) = N,N-bis[(3,5-dimethylpyrazole-1-yl)-methyl]benzylamine with X = H(1), OMe(2), Me(3) and Cl(4)), have been synthesized and characterized by the single crystal X-ray diffraction method. In these complexes, each copper(ii) center is penta-coordinated with square-pyramidal geometry. In addition to the tridentate L(X) ligand, a chloride ion occupies the last position of the square plane. This chloride ion is also bonded to the neighboring Cu(ii) site in its axial position forming an SP-I dinuclear Cu(ii) unit that exhibits small intramolecular ferromagnetic interactions and supported by DFT calculations. The complexes 1-3 exhibit methylmonooxygenase (pMMO) behaviour and oxidise 4-tert-butylcatechol (4-TBCH(2)) with molecular oxygen in MeOH or MeCN to 4-tert-butyl-benzoquinone (4-TBQ), 5-methoxy-4-tert-butyl-benzoquinone (5-MeO-4-TBQ) as the major products along with 6,6'-Bu(t)-biphenyl-3,4,3',4'-tetraol and others as minor products. These are further confirmed by ESI- and FAB-mass analyses. A tentative catalytic cycle has been framed based on the mass spectral analysis of the products and DFT calculations on individual intermediates that are energetically feasible