A new algorithm has been developed to simulate two-dimensional (2D) spectra with correlated anisotropic frequencies faster and more accurately than previous methods. The technique uses finite-element numerical integration on the sphere an interpolation scheme based Alderman-Solum-Grant algorithm. This method is particularly useful for calculations of joint probability distribution functions involving quantities a parametric orientation dependence. technique's efficiency also allows practical...

An approach is presented for simulating multipulse nuclear magnetic resonance (NMR) spectra of polycrystalline solids directly in the frequency domain. The integrates symmetry pathway concept NMR with efficient algorithms calculating spinning sideband amplitudes and performing interpolated finite-element numerical integration over all crystallite orientations a sample. efficiency achieved through set assumptions used to approximate evolution sparse density matrix pulse sequence as individual...

The open-source Python package, MRSimulator, is presented as a simple-to-use, fast, versatile, and extendable package capable of simulating one- higher-dimensional Nuclear Magnetic Resonance (NMR) spectra under static, magic-angle, variable-angle conditions. High benchmarks in spectral simulations are achieved by assuming that there no degeneracies the energy eigenstates, i.e., all dipolar couplings weak limit rotational resonances during evolution periods. Under these assumptions, symmetry...

The Core Scientific Dataset (CSD) model with JavaScript Object Notation (JSON) serialization is presented as a lightweight, portable, and versatile standard for intra- interdisciplinary scientific data exchange. This supports datasets p-component dependent variable, {U0, …, Uq, Up−1}, discretely sampled at M unique points in d-dimensional independent variable (X0, Xk, Xd−1) space. Moreover, this sampling over an orthogonal grid, regular or rectilinear, where the principal coordinate axes of...

A two-dimensional (2D) $J$-resolved magic-angle spinning nuclear magnetic resonance (NMR) spectrum of silica glass at $^{29}\mathrm{Si}$ natural abundance levels, 4.7%, was measured using the shifted-echo phase-incremented echo train acquisition (SE-PIETA) pulse sequence. At levels ${J}_{\text{Si-O-Si}}$ coupling splittings appear as overlapping doublet patterns arising from isolated $^{29}\mathrm{Si}\ensuremath{-}\mathrm{O}\ensuremath{-}^{29}\mathrm{Si}$ linkages. The experimental 2D is...

Many linear inversion problems involving Fredholm integrals of the first kind are frequently encountered in field magnetic resonance. One important application is direct a solid-state nuclear resonance (NMR) spectrum containing multiple overlapping anisotropic subspectra to obtain distribution tensor parameters. Because ill-conditioned nature this inverse problem, we investigate use truncated singular value decomposition and smooth least absolute shrinkage selection operator based...

Employing the concept of effective Hamiltonians, an analytical theory is introduced to describe transitions in a multi-level system nuclear magnetic resonance (NMR) spectroscopy. Specifically, discussion centered towards treatment selective and non-selective excitations static quadrupolar spin (I > 1/2) systems. To this end, radiofrequency (RF) Hamiltonians based on spherical tensor formalism are proposed for describing both integral = 1, 2 3) half-integral 3/2, 5/2 7/2) spins. The optimum...

The dependence of a ²⁹Si geminal <italic>J</italic> coupling across the inter-tetrahedral linkage on local structure was examined using first-principles DFT calculations.

With the development of technology and improved understanding nuclear spin-spin interactions their behavior in static/oscillating magnetic fields, NMR spectroscopy has emerged as a powerful tool for characterizing molecular structure wide range systems chemical, physical biological relevance. Here this article, we revisit important connection between "Secular-Approximation" (a well-known fundamental concept) spectroscopy. Employing recent experimental results background, an alternate...

In this article, a simple heuristic approach that is in agreement with the density operator formalism presented for understanding mechanism of multi-quantum (MQ) excitation half-integral quadrupolar systems. Employing population level diagram nuclear spin states, effect radio-frequency (RF) pulses on multi-level systems described. Based approach, alternate schemes involve non-equilibrium states are proposed improving sensitivity MQ experiments 3/2 and 5/2 Additionally, utility frequency...

A modified shifted-echo PIETA pulse sequence is developed to acquire natural abundance 29 Si 2D J -resolved spectra in crystalline silicates.

A simplified theoretical description of multiple-quantum excitation and mixing for nuclear magnetic resonance half-integer quadrupolar nuclei is presented. The approach recasts the nutation behavior in terms reduced curves through a scaling first-order offset frequency by coupling constant. two-dimensional correlation static anisotropic line shape to second-order magic-angle-spinning (MAS) utilized transform three-dimensional integral over three Euler angles into single dimensionless...

The ratio of Si-29 nuclear magnetic resonance coherence lifetimes for Q 4 and 3 sites under magic-angle spinning a π-pulse train in silicate glasses can detect phase separation, even at small scales where the glass appears optically homogenous.

Abstract In this contribution, the relaxation and diffusional behaviors of low viscous fluids, water methanol confined into mesoporous silica controlled size pore glass were investigated. The engineered porous systems are relevant to geologically important subsurface energy materials. proxies characterized by Brunauer–Emmett–Teller (BET) surface analyzer, nuclear magnetic resonance (NMR) spectroscopy, electron microscopy (EM) determine area, pore-wall protonation morphology these materials,...