Abstract
Multiple pulse sequences are widely used for signal enhancement in NQR detection applications. Since the various 14N 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 14N spin-lattice relaxation times T1 is interpreted as due to hindered rotation of the NO2 group about the C-NO2 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.
Original language | English |
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Pages (from-to) | 61-66 |
Number of pages | 6 |
Journal | Solid State Nuclear Magnetic Resonance |
Volume | 71 |
Early online date | 28 Sept 2015 |
DOIs | |
Publication status | Published - 1 Oct 2015 |
Keywords
- N NQR
- NQR parameters
- NQR relaxation times
- Pulsed spin-locking (PSL) sequence
- Temperature variation
- TNT detection