Visualization and quantitative analysis of spatiotemporal behavior in a first-order thermal spin transition: A stress-driven multiscale process

2011 ◽  
Vol 84 (9) ◽  
Author(s):  
A. Slimani ◽  
F. Varret ◽  
K. Boukheddaden ◽  
C. Chong ◽  
H. Mishra ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Spin Transition ◽  
First Order ◽  
Spatiotemporal Behavior

Pressure effect investigated with first-order reversal-curve method on the spin-transition compounds [FexZn1−x(btr)2(NCS)2] · H2O (x=0.6,1)

2011 ◽  
Vol 83 (22) ◽  
Author(s):  
Aurelian Rotaru ◽  
Jorge Linares ◽  
François Varret ◽  
Epiphane Codjovi ◽  
Ahmed Slimani ◽  
...  
Keyword(s):  
Pressure Effect ◽  
Spin Transition ◽  
First Order ◽  
Curve Method

scholarly journals N.M.R. studies of ligand exchange on acetylacetonatotrimethylplatinum(IV)

1975 ◽  
Vol 28 (4) ◽  
pp. 759 ◽  
Author(s):  
NS Ham ◽  
JR Hall ◽  
GA Swile
Keyword(s):  
Activation Energy ◽  
Quantitative Analysis ◽  
Ligand Exchange ◽  
Variable Temperature ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Cdcl3 Solution ◽  
Made In

A quantitative analysis of the variable-temperature 1H N.M.R. spectra of acetylacetonatotrimethyl-platinum(IV) has been made. In CDCl3 solution the exchange of acetylacetonate ligands is a first-order reaction and proceeds predominantly by dissociation of the dimer into two separated five-coordinate activated complexes. The activation energy is 61.5 � 0.8 kJ mol-1.

First-order reversal curve analysis of spin-transition thermal hysteresis in terms of physical-parameter distributions and their correlations

2005 ◽  
Vol 71 (1) ◽  
Author(s):  
Radu Tanasa ◽  
Cristian Enachescu ◽  
Alexandru Stancu ◽  
Jorge Linares ◽  
Epiphane Codjovi ◽  
...  
Keyword(s):  
Physical Parameter ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Curve Analysis ◽  
First Order ◽  
Parameter Distributions

scholarly journals Magnetic Collapse and the Behavior of Transition Metal Oxides: FeO at High Pressures

1997 ◽  
Vol 499 ◽  
Author(s):  
R. E. Cohen ◽  
Y. Fei ◽  
R. Downs ◽  
I. I. Mazin ◽  
D. G. Isaak
Keyword(s):  
Transition Metal Oxides ◽  
High Pressures ◽  
Local Density ◽  
Hexagonal Phase ◽  
Spin Transition ◽  
Generalized Gradient ◽  
Augmented Plane Wave ◽  
First Order ◽  
First Order Transition ◽  
Linearized Augmented Plane Wave

ABSTRACTLinearized augmented plane wave (LAPW) results are presented for FeO at high pressures using the Generalized Gradient Approximation (GGA) to study the high-spin low-spin transition previously predicted by LAPW with the Local Density Approximation (LDA) and Linear Muffin Tin Orbital (LMTO-ASA) methods within the GGA. We find a first-order transition at a pressure of about 105 GPa for the cubic lattice, consistent with earlier LAPW results, but much lower than obtained with the LMTO. The results are generally consistent with recent Mössbauer experiments that show a transition at about 100 GPa. We also discuss the origin of the transition, and show that it is not due to electrostatic crystal-field effects, but is rather due to hybridization and band widening with pressure. Examination of experimental data and computations suggest that the high pressure hexagonal phase of FeO is likely a polytype between the B8 NiAs and anti-B8 AsNi structures. The former is predicted to be an antiferromagnetic metal, and the latter an antiferromagnetic insulator. Implications for geophysics are discussed.

scholarly journals Quantitative analysis of transformed ray transferences of optical systems in a space of augmented Hamiltonian matrices*

2007 ◽  
Vol 66 (2) ◽  
Author(s):  
W. F. Harris
Keyword(s):  
Quantitative Analysis ◽  
Arithmetic Mean ◽  
Optical Systems ◽  
First Order ◽  
Human Eye ◽  
General Methodology ◽  
Optical Character

There is a need for methods for quantitative analysis of the first-order optical character of optical systems including the eye and components of the eye.  Because of their symplectic nature ray transferences themselves are not closed under addition and multiplication by ascalar and, hence, are not amenable to conventional quantitative analysis such as the calculation of an arithmetic mean.  However transferences can be transformed into augmented Hamiltonian matrices which are amenable to such analysis.  This paper provides a general methodology and in particular shows how to calculate means and variance-covariances representing the first-order optical character of optical systems.  The systems may be astigmatic and may have decentred elements.  An accompanying paper shows application to the cornea of the human eye with allowance for thickness.

scholarly journals Evidence of Photo-Thermal Effects on the First-Order Thermo-Induced Spin Transition of [{Fe(NCSe)(py)2}2(m-bpypz)] Spin-Crossover Material

2019 ◽  
Vol 5 (2) ◽  
pp. 21 ◽  
Author(s):  
Kamel Boukheddaden ◽  
Houcem Fourati ◽  
Yogendra Singh ◽  
Guillaume Chastanet
Keyword(s):  
Thermal Effects ◽  
Spin Crossover ◽  
Evolution Equations ◽  
Thermal Hysteresis ◽  
Magnetic Measurements ◽  
Equations Of Motion ◽  
Spin Transition ◽  
Thermal Bath ◽  
Trapping Region ◽  
First Order

We have investigated by means of optical microscopy and magnetic measurements the first-order thermal spin transition of the [{Fe(NCSe)(py)2}2(m-bpypz)] spin-crossover compound under various shining intensities, far from the light-induced spin-state trapping region. We found evidence of photo-heating effects on the thermally-induced hysteretic response of this spin-crossover material, thus causing the shift of the thermal hysteresis to lower temperature regions. The experimental results are discussed in terms of the apparent crystal temperature and are analyzed theoretically using two evolution equations of motion, written on the high-spin (HS) fraction and heat balance between the crystal and the thermal bath. A very good qualitative agreement was found between experiment and theory in the stationary regime, explaining the experimental observations well and identifying the key factors governing these photo-thermal effects.

scholarly journals Quantitative analysis of proton-linked transport system. β-Galactoside exit in Escherichia coli

1980 ◽  
Vol 188 (2) ◽  
pp. 467-473 ◽  
Author(s):  
I R Booth ◽  
W A Hamilton
Keyword(s):  
Escherichia Coli ◽  
Quantitative Analysis ◽  
Transport System ◽  
Rate Constants ◽  
The Other ◽  
First Order ◽  
First Order Kinetics ◽  
Solute Accumulation ◽  
External Ph

The exit of lactose and thiomethyl-beta-D-galactoside from Escherichia coli ML308-225 has been studied to determine the role of carrier-dependent (zero-trans efflux) and carrier-independent (leak) processes. On the basis of its sensitivity to p-chloromercuribenzene sulphonate the exit of lactose was found to be almost wholly mediated by the carrier. Consistent with this conclusion was the finding that the rate of exit of this sugar was dependent on the external pH, being considerably slower at acid pH. On the other hand exit of thiomethyl-beta-D-galactoside was found to be composed of both carrier-dependent and carrier-independent processes. Both processes exhibited first-order kinetics with the rate constants for zero-trans efflux and leak being 0.137 min-1 and 0.079 min-1, respectively. The relevance of these findings for out earlier proposal for the methods of attenuation of solute accumulation is discussed [Booth, Mitchell & Hamilton (1979) Biochem. J. 182, 687–696].

scholarly journals Neutron powder diffraction studies of two spin transition FeIIcomplexes under pressure

2008 ◽  
Vol 41 (3) ◽  
pp. 637-640 ◽  
Author(s):  
Vincent Legrand ◽  
Frédéric Le Gac ◽  
Philippe Guionneau ◽  
Jean-François Létard
Keyword(s):  
Ambient Temperature ◽  
Powder Diffraction ◽  
Structural Transition ◽  
Spin Crossover ◽  
Spin Transition ◽  
Neutron Powder Diffraction ◽  
Continuous Transition ◽  
First Order ◽  
New Type ◽  
Symmetry Change

The pressure dependences of the lattice parameters of two spin transition compounds have been derived from neutron powder diffraction measurements at ambient temperature. The study of Fe(PM–AzA)2(NCS)2[PM isN-2′-pyridylmethylene and AzA is 4-(phenylazo)aniline] has been used to validate this new type of investigation of spin crossover compounds, and the study of Fe(PM–BiA)2(NCS)2(BiA is 4-aminobiphenyl) has allowed the atypical spin crossover behaviour of this compound under pressure to be explained. In addition, this complex exhibits a pressure-induced structural transition with an associated symmetry change, inducing the transformation of Fe(PM–BiA)2(NCS)2into a different polymorph that avoids a first-order spin transition in favour of continuous transition.

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