No abstract

The molecular beam electric resonance technique has been used to examine the hyperfine spectrum of LiI7 to determine the nuclear hexadecapole interaction of the iodine nucleus. The nuclear magnetic octupole interaction was also considered but found to be marginally significant. A total of 172 transitions in vibrational states 0-3 and rotational states 1-6 have been included in a fit to determine the iodine nuclear quadrupole, spin-rotation, and hexadecapole interactions, the lithium quadrupole and spin-rotation interactions, and the tensor and scalar parts of the spin-spin interaction. Vibration and rotation dependencies of these constants have been determined. The results include: eHh=−0.0151(30), eQIqI=−194351.212(17)−8279.521(46)(v+1/2)+100.616(34)(v+1/2)2−0.3949(73)(v+1/2)3−6.41977(50)J(J+1)+0.10593(33)(v+1/2)J(J+1),eQLiqLi=172.613(52)−3.26(14)(v+1/2)+0.00145(87)J(J+1),cI=6.80260(32)+0.00303(49)(v+1/2)−0.000118(13)J(J+1), cLi=0.75872(72)−0.0088(11)(v+1/2), c3=0.62834(68)−0.0050(11)(v+1/2), c4=0.06223(36)+0.00041(26)(v+1/2), and eΩIωI′=0.000112(73), all in kHz with one standard deviation uncertainties for the last 2 digits in ( ).

Single crystals of the cubic perovskite host, potassium tantalate (KTa0 3 ), doped with iron group, lanthanide, and actinide impurities have been investigated using the technique of electron paramagnetic resonance (EPR). The EPR spectra of Yb 3 + and US + have been observed for the first. time in potassi~m tan~ate by employing crystals co-doped with both impurities. Multiple dopIng of the matenal dunng the crystal growth process avoided the production of semiconducting KTa0 3 and resulted in the incorporation of adequate concentrations of the trivalent lanthanide ion Yb H . The EPR results indicate that Yb 3 + occupies a site in which the local symmetry is axial as a result of nearby charge compensation. Pentavalent uranium is found to occupy a substitutional cubic symmetry site. EPR investigations of Cu 2 +, Co 2 + , Mn 2 + , Ni 3 +, and Fe H were also carried out.

The molecular beam electric resonance technique has been used to examine the hyperfine spectrum of CsF to determine the nuclear quadrupole interaction of the cesium nucleus. A total of 95 transitions in vibrational states vϭ0Ϫ5 and rotational states Jϭ1Ϫ8 have been included in a fit to determine the cesium nuclear quadrupole and spin-rotation interactions, the fluorine spin-rotation interaction, and the tensor and scalar parts of the spin-spin interaction. Vibration and rotation dependencies of these constants have been determined, allowing correction for zero point vibration effects. This experimental Cs nuclear quadrupole coupling constant when combined with the electric field gradient calculated using a relativistic coupled cluster method yields a nuclear quadrupole moment of the Cs nucleus equal to eQϭϪ3.43098 mbarn. The vibrational dependence of the coupling constant is smaller than the theoretical estimate. The coupling constants we have determined are the following: eQ Cs q Cs ϭ1245.598(10)Ϫ14.322(25)(vϩ1/2)ϩ0.080(14) ϫ(vϩ1/2) 2 ϩ0.0040(22)(vϩ1/2) 3 Ϫ0.00209(59)J(Jϩ1)ϩ0.00048(40)(vϩ1/2)J(Jϩ1), c Cs ϭ0.66177(14)Ϫ0.01509(28)(vϩ1/2)ϩ0.000550(94)(vϩ1/2) 2 , c F ϭ15.08163(84)Ϫ0.1744(14) ϫ(vϩ1/2)ϩ0.00234(41)(vϩ1/2) 2 Ϫ0.000093(13)J(Jϩ1), c 3 ϭ0.92713(53)Ϫ0.00917(93)(v ϩ1/2)ϩ0.00097(29)(vϩ1/2) 2 , c 4 ϭ0.62745(30)Ϫ0.00903(22)(vϩ1/2). All values are in kHz units, with one standard deviation uncertainty estimates in the last two digits shown in ().

No abstract