An adaptive method for computing resonance fields for continuous-wave EPR spectra

We present an efficient method for computing resonance fields for cw EPR that adaptively models the state energies over a given field range with cubic splines. The method diagonalizes the spin Hamiltonian matrix for suitably chosen fields, which are determined by an adaptive iterative bisection procedure. Resonance fields are computed from the cubic spline model. The new method adapts to the complexity of the spin system and keeps the number of diagonalizations minimal. For systems with field-independent interactions (FII) small compared to the spectrometer frequency ν0 only three diagonalizations are needed, for high-spin systems with FII larger than ν0 up to 60 diagonalizations are necessary.

[1]  G. Garton,et al.  E.p.r. and endor of Tb4+ in thoria , 1965, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[2]  A. Kreiter,et al.  Simultaneous EPR and ENDOR powder-spectra synthesis by direct hamiltonian diagonalization , 1991 .

[3]  T. Yen.  Electron Spin Resonance of Metal Complexes , 1995 .

[4]  H. Silverstone,et al.  Simulation methods for looping transitions. , 1998, Journal of magnetic resonance.

[5]  Tosio Kato.  A Short Introduction to Perturbation Theory for Linear Operators , 1982 .

[6]  S. Misra,et al.  A rigorous evaluation of spin-Hamiltonian parameters and linewidth from a polycrystalline EPR spectrum. , 1999, Journal of magnetic resonance.

[7]  J. Villafranca,et al.  A program for EPR powder spectrum simulation , 1985 .

[8]  G. V. Veen.  Simulation and analysis of EPR spectra of paramagnetic ions in powders , 1978 .

[9]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[10]  M. Gribnau,et al.  An efficient general algorithm for the simulation of magnetic resonance spectra of orientationally disordered solids , 1990 .

[11]  H. Rinneberg,et al.  EPR Studies of Ti3+sH+ Centers in X-Irradiated a-Quartz , 1972 .

[12]  M. Gribnau,et al.  MAGRES: a general program for electron spin resonance, ENDOR and ESEEM , 1987 .

[13]  Andrew G. Glen,et al.  APPL , 2001 .

[14]  Deming Wang,et al.  New methodologies for computer simulation of paramagnetic resonance spectra , 1996 .

[15]  William H. Press,et al.  Numerical recipes in C , 2002 .

[16]  G. Belford,et al.  Eigenfields: A practical direct calculation of resonance fields and intensities for field-swept fixed-frequency spectrometers , 1973 .

[17]  Harris J. Silverstone,et al.  Simulation of the EMR Spectra of High-Spin Iron in Proteins , 1993 .

[18]  Henry M. Gladney,et al.  Computer Analysis of Electron Paramagnetic Resonance Spectra , 1964, IBM J. Res. Dev..

[19]  Morin,et al.  Modeling EPR powder spectra using numerical diagonalization of the spin hamiltonian , 1999, Journal of magnetic resonance.

[20]  D. Collison,et al.  Electron paramagnetic resonance of d transition metal compounds , 1992 .

[21]  N. Chasteen,et al.  An efficient approach to computer simulation of EPR spectra of high-spin Fe(III) in rhombic ligand fields , 1982 .

[22]  H. Weihe,et al.  Magnetic Susceptibility and EPR Spectra of mu-Cyano-bis[pentaamminechromium(III)] Perchlorate. , 1991 .