Adiabatic Solid Effect
| Autor: | Thach V. Can, Kong Ooi Tan, Ralph T. Weber, Robert G. Griffin |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Nuclear Theory Physics::Medical Physics 02 engineering and technology 021001 nanoscience & nanotechnology Polarization (waves) 01 natural sciences Molecular physics Article 0103 physical sciences Condensed Matter::Strongly Correlated Electrons General Materials Science Irradiation Physical and Theoretical Chemistry Nuclear Experiment 010306 general physics 0210 nano-technology Adiabatic process |
| Zdroj: | J Phys Chem Lett |
| ISSN: | 1948-7185 |
| Popis: | The solid effect (SE) is a two spin dynamic nuclear polarization (DNP) mechanism that enhances the sensitivity in NMR experiments by irradiation of the electron–nuclear spin transitions with continuous wave (CW) microwaves at ω(0S) ± ω(0I), where ω(0S) and ω(0I) are electron and nuclear Larmor frequencies, respectively. Using trityl (OX063), dispersed in a 60/40 glycerol/water mixture at 80 K, as a polarizing agent, we show here that application of a chirped microwave pulse, with a bandwidth comparable to the EPR line width applied at the SE matching condition, improves the enhancement by a factor of 2.4 over the CW method. Furthermore, the chirped pulse yields an enhancement that is ~20% larger than obtained with the ramped-amplitude NOVEL (RA-NOVEL), which to date has achieved the largest enhancements in time domain DNP experiments. Numerical simulations suggest that the spins follow an adiabatic trajectory during the polarization transfer; hence, we denote this sequence as an adiabatic solid effect (ASE). We foresee that ASE will be a practical pulsed DNP experiment to be implemented at higher static magnetic fields due to the moderate power requirement. In particular, the ASE uses only 13% of the maximum microwave power required for RA-NOVEL. |
| Databáze: | OpenAIRE |
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