WSolids1 is a program for the visualization and analysis of processed one-dimensional solid-state NMR data. Although there are several ”general purpose” programs or libraries available to calculate many interactions and for many different experiments, there is still room for programs with specially designed speciﬁc calculation models. The main reason is efﬁciency. A routine designed for one particular purpose will always be more efﬁcient than a general purpose routine! Progress in computing power continually decreases the gap. However, calculation of a static powder pattern of an isolated spin pair using a general purpose program still requires several hours as compared to the few seconds using the less general implementation in WSolids.
Main Features :
- save everything as a self-contained WSolids document (in XML format);
- runs under MS Windows 9x, NT 4, 2000, XP, 7 to simulate solid-state NMR spectra (it does not iterate)
- calculations typically take a few seconds to complete
- an experimental spectrum can be read in one of the following formats: Bruker (TopSpin, XWinNMR, WinNMR, WinNMR ASCII), Chemagnetics Spinsight, and a native ASCII format
- calculated spectra can be displayed in absorption, first derivative, or second derivative mode
- output of calculated spectra is in TopSpin, WinNMR or Solids format. WinNMR, TopSpin or a similar program (e.g., SpecPlot)is used for plotting
Supported Calculation Models:
1. Static: Chemical shift anisotropy : Spectrum of a static powder sample showing chemical shift anisotropy ("powder pattern").
2. Static: Dipolar-chemical shift (A2, AX) : Chemical shift anisotropy, direct dipole-dipole coupling and indirect spin-spin coupling for a homonuclear pair of equivalent spin-1/2 nuclei (A2 approximation) or a heteronuclear spin pair in a static powder sample (AX approximation).
3. Static: Dipolar-Chemical Shift (AB) : Chemical shift anisotropy, direct dipole-dipole coupling and indirect spin-spin coupling for a homonuclear pair of spin-1/2 nuclei, including "second-order" effects, in a static powder sample (AB).
4. Static: Quadrupolar Nucleus : Quadrupolar interaction up to second order for the observed nucleus, including chemical shift anisotropy, for a static powder sample. Optionally, dipolar and indirect coupling to a heteronucleus can be added (note: quadrupolar interaction, if any, is neglected for the coupled heteronucleus).
5. MAS: Chemical shift anisotropy (HB) : Spectrum of a powder sample spinning at the magic angle, showing chemical shift anisotropy; uses Herzfeld-Berger tables.
6. MAS: Quadrupolar nucleus : Spectrum of central transition of a quadrupolar nucleus in a powder sample spinning rapidly at the magic angle.
7. MAS: Spin-1/2 -- Spin-S (Diag.) : Considers spin-spin interactions with a quadrupolar nucleus under magic-angle spinning, using full matrix diagonalization.
8. MAS: Spin-1/2 -- Spin-S (Stick) : Considers spin-spin interactions with quadrupolar nuclei under magic-angle spinning, using first-order perturbation theory and "stick" approach.
9. MAS: Spin-1/2 -- Spin-S (Shape) : Considers spin-spin interactions with a quadrupolar nucleus under magic-angle spinning, using first-order perturbation theory to calculate the line shape.
10. VAS: Dipolar-chemical shift (A2, AX) : Considers chemical shift and spin-spin interactions for a homo- or heteronuclear pair of nuclei, i.e. A2 or AX approximation, under variable-angle spinning (fast spinning limit).
11. VAS: Dipolar-chemical shift (AB) : Considers chemical shift and spin-spin interactions for a homonuclear pair of nuclei, i.e. AB approximation, under variable-angle spinning (fast spinning limit)