Generalization of the lineshape useful in magnetic resonance spectroscopy

Howarth, David F.; Weil, John A.; Zimpel, Zbigniew

doi:10.1016/s1090-7807(02)00195-7

Cited by 32 publications

(22 citation statements)

References 12 publications

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“…Defect concentrations were found using spin counting EPR techniques in a previous study [14]. derivative Tsallian lineshapes [19]. To avoid baseline problems and for more accurate results [20], double integration was carried out on line fits of the derivative spectra.…”

Section: Experimental Methodsmentioning

confidence: 99%

Influence of magnetic field alignment and defect concentration on nitrogen-vacancy polarization in diamond

2015

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We present a quantitative, systematic study of the polarization of the Zeeman magnetic sublevels of the NV-defect in diamond as a function of magnetic field alignment relative to the NV-defect axis. The orientation dependence of NV-polarization in the lab frame is accounted for by a Wigner rotation of a constant defect frame polarization. We also find that the NV-defect level polarizations vary with the P1 defect concentration, and that the polarization of the m s =0 state with optical pumping decreases from 46% to 36% in samples as P1 concentrations vary from 20 ppm to 100 ppm, respectively. OPEN ACCESS RECEIVED

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Section: Experimental Methodsmentioning

confidence: 99%

Influence of magnetic field alignment and defect concentration on nitrogen-vacancy polarization in diamond

2015

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“…A Tsallis function was used to produce the simulated spectra since EPR line shapes are usually not well reproduced with Lorentzian or Gaussian functions. 33 Furthermore, the algorithm utilizes the pseudomodulation technique to account for the distortion of the EPR line shape due to field modulation. Defect concentrations were calculated by comparing the EPR signal intensities to that of a reference sample of known concentration.…”

Section: Methodsmentioning

confidence: 99%

Optical properties of the neutral silicon split-vacancy center in diamond

et al. 2011

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The zero-phonon line (ZPL) at 1.68 eV has been attributed to the negatively charged silicon split-vacancy center in diamond, (Si-V) − , and has been extensively characterized in the literature. Computational studies have predicted the existence of the neutral charge state of the center, (Si-V) 0 , and it has been experimentally observed using electron paramagnetic resonance (EPR). However, the optical spectrum associated with (Si-V) 0 has not yet been conclusively identified. In this paper the 1.31 eV band visible in luminescence and absorption is attributed to (Si-V) 0 using an approach which combines optical absorption and EPR measurements. The intensities of both 1.68 eV and 1.31 eV bands are found to increase in deliberately Si-doped chemical vapor deposition (CVD) grown diamond, and also after electron irradiation and annealing, suggesting the involvement of both Si and a vacancy in the centers. The 1.31 eV ZPL is unambiguously associated to Si by its shift to a lower energy when the dominant Si isotope is changed from 28 Si to 29 Si. Charge transfer between (Si-V) − and (Si-V) 0 induced via ultraviolet photoexcitation or heating in the dark allows calibration factors relating the integrated absorption coefficient of their respective ZPLs to the defect concentration to be determined. Preferential orientation of (Si-V) 0 centers in CVD diamond grown on {110}-oriented diamond substrates is observed by EPR. The (Si-V) 0 centers are shown to grow predominantly into CVD diamond as complete units, rather than by the migration of mobile vacancies to substitutional Si (Si S ) atoms. Corrections for the preferential alignment of trigonal centers for quantitative analysis of optical spectra are proposed and the effect is used to reveal that the 1.31 eV ZPL arises from a transition between the 3 A 2g ground state and 3 A 1u excited state of (Si-V) 0 . A simple rate equation model explains the production of (Si-V) 0 upon irradiation and annealing of Si-doped CVD diamond. In as-grown Si-doped diamond the (Si-V) defects only account for a fraction of the total silicon present; the majority being incorporated as Si S . The data show that both Si S and (Si-V) are effective traps for mobile vacancies.

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“…(3) We have examined the ν + 870 kHz spectral line of monoclinic TNT at various temperatures and found the line shape to be a good fit to a Lorentzian profile for which the full width at half height ∆ν 1/2 is related to the signal decay time T 2 * via ∆ν 1/2 = 1/(πT 2 * ). Lorentzian line shapes are expected when the dominant term is damping of the Larmor precession of the magnetization in the electric field gradient due to relaxation [32]. The temperature variation of ∆ν 1/2 is shown in Fig.…”

Section: Tablementioning

confidence: 94%

14N NQR, relaxation and molecular dynamics of the explosive TNT

Smith

Rowe

Althoefer

et al. 2015

Solid State Nuclear Magnetic Resonance

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Multiple pulse sequences are widely used for signal enhancement in NQR detection applications. Since the various 14 N NQR relaxation times, signal decay times and frequency of each NQR line have a major influence on detection sequence performance, it is important to characterise these parameters and their temperature variation, as fully as possible. In this paper we discuss such measurements for a number of the ν + and ν − NQR lines of monoclinic and orthorhombic TNT and relate the temperature variation results to molecular dynamics. The temperature variation of the 14 N spin-lattice relaxation times T 1 is interpreted as due to hindered rotation of the NO 2 group about the C-NO 2 bond with an activation energy of 89 kJ mol -1 for the ortho and para groups of monoclinic TNT and 70 kJ mol -1 for the para group of orthorhombic TNT.

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Generalization of the lineshape useful in magnetic resonance spectroscopy

Cited by 32 publications

References 12 publications

Influence of magnetic field alignment and defect concentration on nitrogen-vacancy polarization in diamond

Influence of magnetic field alignment and defect concentration on nitrogen-vacancy polarization in diamond

Optical properties of the neutral silicon split-vacancy center in diamond

14N NQR, relaxation and molecular dynamics of the explosive TNT

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