Study of molecular reorientation and quantum rotational tunneling in tetramethylammonium selenate by 1H NMR.
1H NMR spin-lattice relaxation time measurements have been carried out in [(CH3)4N]2SeO4 in the temperature range 389-6.6 K to understand the possible phase transitions, internal motions and quantum rotational tunneling. A broad T1 minimum observed around 280 K is attributed to the simultaneous motions of CH3 and (CH3)4N groups. Magnetization recovery is found to be stretched exponential below 72 K with varying stretched exponent. Low-temperature T1 behavior is interpreted in terms of methyl groups undergoing quantum rotational tunneling.
Department of Physics, Bangalore University, Bangalore 560 056, India.
K J
KJ
Mallikarjunaiah
K C
KC
Paramita
K P
KP
Ramesh
R
R
Damle
D003198:Computer Simulation; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011522:Protons; D011789:Quantum Theory; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012399:Rotation; D064586:Selenic Acid; D018036:Selenium Compounds / Q000737:chemistry*; D013113:Spin Labels; D013696:Temperature
D011522:Protons; D000644:Quaternary Ammonium Compounds; D018036:Selenium Compounds; D013113:Spin Labels; C027917:tetramethylammonium; D064586:Selenic Acid