Mallikarjunaiah K.J. Solid-State NMR and its implications in molecular dynamics study: instrumentation, temperature dependent study of slow motions in ammonium and methyl-ammonium super- ionic conductors / K.J.Mallikarjunaiah, R.Damle. - Saarbrücken: LAP LAMBERT Academic Publishing, 2011. - 146 p.: ill. - Ref.: p.137-139. - ISBN 978-3-8443-0676-7  Место хранения:   07 | Центральная библиотека Красноярского научного центра СО РАН | Красноярск

Оглавление / Contents

1 NMR: Basic theory ......................................... 1-29 1.1 Nuclear Spins in a Static Magnetic field ................ 1 1.2 The Classical Picture of Motion ......................... 4 1.3 Quantum mechanical Picture- Spin Hamiltonian ............ 6 1.3.1 The dipolar Hamiltonian .......................... 6 1.3.2 Method of moments ................................ 8 1.4 Effects of molecular Motions ........................... 11 1.4.1 Line Narrowing .................................. 11 1.4.2 Relaxation ...................................... 12 1.4.2.1 Dipole-dipole interaction .............. 12 1.4.2.2 Translational diffusion ................ 18 1.4.2.3 Tunneling reorientation ................ 20 1.5 Free induction Decay ................................... 23 1.6 Measurement of M2 and T1 ............................... 24 1.6.1 Second moment (M2) .............................. 24 1.6.2 Spin lattice relaxation (Ti) .................... 24 1.6.2.1 Inversion Recovery Method (π-τ-π/2) .... 24 1.6.2.2 Saturation Burst method ................ 26 References .................................................. 28 2 NMR Instrumentation and Experimental techniques .......... 30-61 2.1 Introduction ........................................... 30 2.2 Wide-line NMR spectrometer ............................. 30 2.2.1 Electromagnet ................................... 31 2.2.2 Oscillator ...................................... 32 2.2.3 Modulation and lock in detection ................ 33 2.2.4 Signal acquisition and Automation ............... 39 2.3 Pulsed NMR spectrometer ................................ 43 2.3.1 PC controlled programmable pulse generator ...... 45 2.3.2 Transmitter ..................................... 48 2.3.2.1 RFunit ................................. 49 2.3.2.2 Medium power amplifier ................. 49 2.3.2.3 High power amplifier ................... 51 2.3.3 The NMR Probe Circuit ........................... 52 2.3.3.1 Series resonant circuit ................ 52 2.3.3.2 Parallel resonant circuit .............. 53 2.3.4 Receiver ........................................ 54 2.4 Temperature variation setup ........................... 56 2.4.1 High temperature assembly ....................... 56 2.4.2 Liquid Nitrogen Assembly ........................ 57 2.4.3 Liquid Helium Assembly .......................... 58 References .................................................. 60 3 NMR Studies in Diammonium hexafluorozirconate ............ 62-79 3.1 Introduction ........................................... 62 3.2 Earlier studies ........................................ 64 3.3 Results and discussion ................................. 66 3.3.1 Analysis of 'H NMR T ............................ 66 3.3.3.1 High Temperature (HT) region (410-240 K) ............................ 67 3.3.3.2 Intermediate temperature range (240-146 K) ............................ 69 3.3.3.3 Low Temperature (LT) region (146-11 K) ............................. 71 3.3.2 Analysis of 19F NMR T1 .......................... 74 3.3.2.1 High Temperature (HT) region (410-240 K) ............................ 74 3.3.2.2 Intermediate temperature range (200-106 K) ............................ 75 3.3.2.3 Low temperature range (106-20 K) ....... 75 3.4 Conclusion ............................................. 75 References .................................................. 77 4 NMR Studies in Tetramethylammonium (TMA) Salts .......... 80-110 4.1 Tetramethylammonium Selenate ((CH3)4N)2SeO4 ............ 81 4.1.1 Introduction .................................... 81 4.1.2 Earlier studies ................................. 81 4.1.3 Sample preparation and characterization ......... 84 4.1.4 Results and discussion .......................... 84 4.1.4.1 High temperature region (389-170 K) .... 84 4.1.4.2 Low temperature region (72-6.6 K) ...... 89 4.1.5 Conclusions ..................................... 94 4.2 Tetramethylammonium Hexafluorophosphate (CH3)4NPF6 ..... 94 4.2.1 Introduction .................................... 94 4.2.2 Earlier studies ................................. 95 4.2.3 Results and discussion .......................... 97 4.2.3.1 Second moment .......................... 97 4.2.3.2 Spin lattice relaxation time ........... 99 4.2.4 Conclusions .................................... 107 References ................................................. 108 5 NMR Studies in Trichlorogermanates ..................... 111-140 5.1 Introduction .......................................... 111 5.2 Trimethylammonium Trichlorogermanate ((CH3)3NGeCl3) ... 112 5.2.1 Earlier studies ................................ 112 5.2.2 Sample preparation and characterization ........ 113 5.2.3 Results and discussion ......................... 114 5.2.3.1 High temperature region (391-272 K) ... 115 5.2.3.2 Inter mediate temperature region (272 - 100 K) ......................... 117 5.2.3.3 Low temperature region (100-5.2 K) .... 120 5.2.4 Conclusions .................................... 122 5.3 Tetramethylammonium Trichlorogermanate ((CH3)4NGeCl3) ........................................ 124 5.3.1 Earlier studies ................................ 124 5.3.2 Sample preparation and characterization ........ 125 5.3.3 Results and discussion ......................... 127 5.3.3.1 Second moment ......................... 127 5.3.3.2 Spin lattice relaxation time .......... 129 5.3.4 Conclusions .................................... 136 References ............................................ 137 Appendix 1 .................................................... 141 Appendix II ................................................... 142 Publications .................................................. 146