scholarly journals Pentacene in 1,3,5-Tri(1-naphtyl)benzene: A Novel Standard for Transient EPR Spectroscopy at Room Temperature

2021 ◽  
Author(s):  
Mirjam Schröder ◽  
Daniel Rauber ◽  
Clemens Matt ◽  
Christopher W. M. Kay
Keyword(s):  
Epr Spectroscopy ◽  
Room Temperature ◽  
Glass Transition Point ◽  
Zero Field ◽  
Microwave Resonator ◽  
Spectral Simulation ◽  
Zero Field Splitting ◽  
Standard Samples ◽  
Epr Spectrum ◽  
Data Set

AbstractTesting and calibrating an experimental setup with standard samples is an essential aspect of scientific research. Single crystals of pentacene in p-terphenyl are widely used for this purpose in transient electron paramagnetic resonance (EPR) spectroscopy. However, this sample is not without downsides: the crystals need to be grown and the EPR transitions only appear at particular orientations of the crystal with respect to the external magnetic field. An alternative host for pentacene is the glass-forming 1,3,5-tri(1-naphtyl)benzene (TNB). Due to the high glass transition point of TNB, an amorphous glass containing randomly oriented pentacene molecules is obtained at room temperature. Here we demonstrate that pentacene dissolved in TNB gives a typical “powder-like” transient EPR spectrum of the triplet state following pulsed laser excitation. From the two-dimensional data set, it is straightforward to obtain the zero-field splitting parameters and relative populations by spectral simulation as well as the $$B_{1}$$ B 1 field in the microwave resonator. Due to the simplicity of preparation, handling and stability, this system is ideal for adjusting the laser beam with respect to the microwave resonator and for introducing students to transient EPR spectroscopy.

The EPR Zero-Field Splitting D and its Pressure and Temperature Dependence for Trigonal Mn2+ Centers in [Zn(H2O)6](BF4)2:Mn2+ Crystal

2006 ◽  
Vol 61 (5-6) ◽  
pp. 289-292 ◽  
Author(s):  
Hong-Gang Liu ◽  
Xiao-Xuan Wu ◽  
Wen-Chen Zheng ◽  
Lv He
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Coupling Mechanism ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Thermal Expansion Coefficients ◽  
Perturbation Formula ◽  
Expansion Coefficients

The EPR zero-field splitting D (= b02 ) and its pressure and temperature dependence for trigonal Mn2+ centers in low and room temperature phases in [Zn(H2O)6](BF4)2 :Mn2+ crystal are studied by a high-order perturbation formula based on the dominant spin-orbit coupling mechanism. From the studies, the local trigonal distortion angles, the local angular compressibilities and the local angular thermal expansion coefficients for Mn2+ centers in both phases of the [Zn(H2O)6](BF4)2 crystal are estimated. The results are discussed

EPR Study of the Nitrogen Containing Defect Center Created in Self-Assembled 6H SiC Nanostructure

2013 ◽  
Vol 740-742 ◽  
pp. 389-392 ◽  
Author(s):  
Ekaterina N. Kalabukhova ◽  
Dariya Savchenko ◽  
Bela Shanina ◽  
Nikolai T. Bagraev ◽  
Leonid Klyachkin ◽  
...  
Keyword(s):  
The Self ◽  
Zero Field ◽  
Boron Diffusion ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Epr Spectrum ◽  
Defect Center ◽  
Field Splitting ◽  
Splitting Constant ◽  
Self Assembled

Triplet center with spin state S = 1 is detected in the EPR spectrum of the self-assembled 6H SiC nanostructure obtained by non-equilibrium boron diffusion into the n-type 6H SiC epitaxial layer (EL) under conditions of the controlled injection of the silicon vacancies at the temperature of T = 900°C. From the analysis of the angular dependences of the EPR spectrum and the numerical diagonalization of the spin Hamiltonian, the value of the zero-field splitting constant D and g-factor are found to be D = 1140•10-4см-1 and gpar = 1.9700, gper = 1.9964. Based on the hyperfine (hf) structure of the defect originating from the hf interaction with one 14N nuclei, the large value of the zero-field splitting constant D and technological conditions of the boron diffusion into the n-type 6H SiC EL, the triplet center is tentatively assigned to the defect center consisting of nitrogen atom and silicon vacancy.

High-Frequency EPR Spectroscopy of Large Metal Ion Clusters: From Zero Field Splitting to Quantum Tunneling of the Magnetization

1998 ◽  
Vol 31 (8) ◽  
pp. 460-466 ◽  
Author(s):  
Anne-Laure Barra ◽  
Louis-Claude Brunel ◽  
Dante Gatteschi ◽  
Luca Pardi ◽  
Roberta Sessoli
Keyword(s):  
Epr Spectroscopy ◽  
High Frequency ◽  
Quantum Tunneling ◽  
Metal Ion ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Ion Clusters

Fine Structure of Triplet Centers in Room Temperature Irradiated 6H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 403-406 ◽  
Author(s):  
Andreas Scholle ◽  
Siegmund Greulich-Weber ◽  
Eva Rauls ◽  
Wolf Gero Schmidt ◽  
Uwe Gerstmann
Keyword(s):  
Fine Structure ◽  
Room Temperature ◽  
Positive Sign ◽  
Spin Interaction ◽  
Zero Field ◽  
Spin Orbit ◽  
Zero Field Splitting ◽  
Defect Center ◽  
Field Splitting ◽  
Annealing Behavior

In non-annealed 6H-SiC samples that were electron irradiated at room temperature, a new EPR signal due to a S=1 defect center with exceptionally large zero-field splitting (D = +652•10-4 cm-1) has been observed under illumination. A positive sign of D demonstrates that the spin-orbit contribution to the zero-field splitting exceeds by far that of the spin-spin interaction. A principal axis of the fine structure tilted by 59° against the crystal c-axis as well as the exceptionally high zero-field splitting D can be qualitatively understood by the occurrence of additional close-lying defect levels in defect clusters resulting in comparatively large second-order spin-orbit coup¬ling. A tentative assignment to vacancy clusters is supported by the observed annealing behavior.

ESR SPECTRA OF Fe+3 IN SINGLE CRYSTALS OF ANDALUSITE

1966 ◽  
Vol 44 (3) ◽  
pp. 509-523 ◽  
Author(s):  
F. Holuj ◽  
J. R. Thyer ◽  
N. E. Hedgecock
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Esr Spectra ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
K Band

ESR spectra of Fe+3 in andalusite have been investigated at X- and K-band frequencies at room temperature. They have been interpreted on the assumption that Fe+3 occupies the two inequivalent Al+3 sites in andalusite. The spectra show large zero-field splitting. The constants of the conventional orthorhombic spin Hamiltonian which fit the spectra are as follows: for site I: b20 = 15.0 ± 0.1 kG, b22 = 5.0 ± 0.1 kG, and isotropic g = 2.001 ± 0.002; for site II: b20 = 20.1 ± 0.1 kG, b22 = 0.075 ± 0.010 kG, and isotropic g = 2.004 ± 0.0005. A study of the intensities of ESR signals due to site I follow a pattern predicted by theory. The implications of these results are considered briefly.

ELECTRON SPIN RESONANCE OF Fe+3 IN CORDIERITE

1966 ◽  
Vol 44 (11) ◽  
pp. 2749-2755 ◽  
Author(s):  
N. E. Hedgecock ◽  
S. C. Chakravartty
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Esr Spectra ◽  
Orthorhombic Symmetry ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Spin Resonance

ESR spectra of Fe+3 located at one of the aluminium sites in cordierite have been investigated at X- and K-band frequencies at room temperature. The spectra exhibit large zero-field splitting and have been fitted to a spin Hamiltonian of orthorhombic symmetry, having constants b20 = 14.6 ± 0.1 kG, b22 = 8.5 ± 0.1 kG, and isotropic g = 2.004 ± 0.002.

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