| Research Abstract |
The magnetic resonance is a very useful method to investigate the microscopic states of chemical species in liquids. This method, however, has a limit owing to the so-called skin effect, Which is inevitable in highly conducting samples. In particular, usual ESR apparatuses with high frequency (1-35MHz) give limited information on conducting liquids. In this project we will study the electronic states in some alkali metal-ammonia (amine) solutions by ESR and NMR methods, operating at the same frequency around 100 MHz. For this purpose we have set up a low-field ESR apparatus and combine it with an NMR apparatus already available.
Our ESR apparatus is of CW type, the resonance frequency is 195MHz. The field sweeping is from 63 to 76 gauss, and the modulation frequency is 6 KHz. The probe head is made as to operate at low temperatures, form 170 to 250K. The experimental results for lithium-methylamine solutions are summarized as :
(1) The intensity of the ESR spectra per unit amount of diss
… More
olved metal is not a constant, but increases with temperature and decreases with concentration of metal.
(2) The apparent spin-spin relaxation time T_2^* of the electronic spins determined from the spectral width increases with increasing temperature and metal concentration.
(3) The observed spectra symmetric up to 23 mole % metal wnere the solutions is metallic.
In the second year of the project, we have constructed a low-field pulsed ERS apparatus, which can be used for samples with very narrow spectral width, as narrow as 0.02 gauss. We are now trying to prepare suitable samples for the apparatus.
On the other hand, we have measured the electronic properties of some chalcogenide liquid semiconductors modified with thallium and bismuth. We have also measured the chemical potential of thallium and bismuth in molten chalcogenides. We are planning to measure the NMR spectra of these added elements, which have sufficient NMR sensitivity. The ERS of the conduction electrons in these molten semiconductors will be made as well. Less
|
