J. Cederberg

Hyperfine Spectrum of NaCl by Molecular‐Beam Electric Resonance

The hyperfine spectrum of NaCl has been observed at very low field using the molecular‐beam electric resonance method. The Hamiltonian is expressed in a representation in which the combined quadrupole term is diagonal when the quadrupole interaction constants of the two nuclei are equal. The analysis of the spectrum then gives for the constants X+ ≡ [(eqQ)Na + (eqQ)Cl] / 2, X− ≡ [(eqQ)Na − (eqQ)Cl] / 2, c+ ≡  (c1 + c2) / 2, c3, and c4 the values (in kilohertz) for 23Na35Cl: X+ = − 5658.0 ± 0.1, X− = − 16 ± 50, c+ = + 0.51 ± 0.01, c3 = + 0.22 ± 0.02, and c4 = + 0.05 ± 0.03 for v = 0; X+ = − 5716.3 ± 0.5 and X− = + 116 ± 20 for v = 1; X+ = − 5772.6 ± 0.7 and X− = + 235 ± 12 for v = 2; and X+ = − 5828 ± 1 and X− = + 340 ± 15 for v = 3. Lines have also been observed corresponding to 23Na35Cl, J = 2, and 23Na37Cl, J = 1.

The hyperfine spectrum of sodium bromide

Abstract The molecular beam electric resonance technique has been used to examine in detail the hyperfine spectrum of both isotopes of NaBr in vibrational states v = 0–5 and rotational states J = 2–6. Frequencies of 166 observed transitions have been measured with a precision of a few hertz by extrapolating the experimental frequencies to zero field. State-dependent molecular hyperfine constants have been determined for the quadrupole, spin-rotation, spin-spin, and octupole interactions, fitting the spectrum to a reduced χ 2 of 3.39 for Na 79 Br and 1.55 for Na 81 Br.

Beam maser spectrum of the 111→101 transition of ND2H and the hyperfine structure of the ammonia molecule

The structure of the 111→101 transition of ND2H has been studied by means of millimetre-wave beam maser spectroscopy. Twenty-five components which result from the nitrogen, deuterium, and hydrogen hyperfine interactions have been resolved and theoretically analysed. The theory of three identical particles is discussed and used to fit the beam measer spectra of the J = K = 4 and J = K = 6 inversion transitions of ND3 which have been reported previously. These results are compared with those of the submillimetre-wave beam maser spectrum of the J = 1 →0 transition of ND3. By use of molecular and isotopic relations, the results of this work are critically compared with previous centimetre-wave beam maser studies of NH3 and NH2D.

The hyperfine spectrum of KF

Abstract A molecular beam electric resonance spectrometer was used to observe the hyperfine spectrum of KF, including both K isotopes, vibrational states 0–7 and rotational states 1–3. The 73 observed transitions were fitted with 14 parameters expressing the vibrational and rotational dependence of each of the molecular hyperfine constants. Experimental uncertainties of the order of 1 Hz were achieved.

Evidence for a nuclear hexadecapole interaction in the hyperfine spectrum of LiI

The molecular beam electric resonance technique has been used to examine the hyperfine spectrum of 7LiI 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(...

The hyperfine spectrum of LiF

Abstract The molecular beam electric resonance technique has been used to examine the hyperfine spectrum of 7Li19F in vibrational states v = 0–4 and rotational states J = 1–6, in addition to a few 6Li19F lines. With the low electric fields used, the spectrum consists of many overlapping lines which have been deconvoluted by fitting the actual Rabi lineshape. The fitting process includes corrections for the small residual Stark shifts in the frequencies, yielding a precision on the order of a few hertz. By fitting the spectrum, new values have been obtained for the nuclear electric quadrupole and magnetic hyperfine parameters, including their dependence on vibrational and rotational state.

Centrifugal distortion effects in the hyperfine spectrum of KCl

The hyperfine spectrum of KCl has been examined at near-zero electric field and zero magnetic field using a molecular beam electric resonance spectrometer. Rotational as well as vibrational shifts have been observed in both nuclear quadrupole interactions. With eqQ = Q00 + Q10(v + 12) + Q20(v + 12)2 + Q01J(J + 1), we find (all in units of kHz) for K in 39K35Cl: Q00 = −5691.47 ± 0.04, Q10 = 51.32 ± 0.06, Q20 = −0.205 ± 0.020, Q01 = 0.014 ± 0.007, Q00(K37Cl) − Q00(K35Cl) = −0.03 ± 0.07; for Cl in 39K35Cl: Q00 = 137.0 ± 0.3, Q10 = −163.2 ± 0.5, Q20 = 1.57 ± 0.15, Q01 = 0.07 ± 0.03, [Q(35Cl)Q(37Cl)]Q00(K37Cl) − Q00(K35Cl) = −0.5 ± 0.6; and magnetic constants cK = 0.154 ± 0.007, cCl = 0.435 ± 0.010, c3 = 0.035 ± 0.012, and c4 = 0.009 ± 0.006. These have been used to provide a mapping of the field gradients at both nuclear sites to fourth order in ξ = (r − re)re. We find eQqK(ξ) = (−5692.5 ± 2.5) + (1.7 ± 0.8) × 104 ξ + (−2. ± 4.) × 104 ξ2 + (−8. ± 18.) × 105 ξ3 + (8. ± 15.) × 106 ξ4 and eQqCl(ξ) = (120. ± 22.) + (8. ± 4.) × 104 ξ + (−5.8 ± 2.0) × 105 ξ2 + (−1.1 ± 1.6) × 107 ξ3 + (1.1 ± 1.3) × 108 ξ4.

The hyperfine interactions in CsF

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 v=0−5 and rotational states J=1−8 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 eQ=−3.43098 mbarn. The vibrational dependence of the coupling constant is smaller than the theoretical estimate. The coupling constants we have determined are the following: eQCsqCs=1245.598(10)−14.322(25)(...

Hyperfine spectra and molecular constants of D2S

Abstract A millimeter wave molecular beam maser has been used to resolve the nuclear hyperfine structure of the 1 10 → 1 01 transition of D 2 S at 91.4 Gc/sec. This data, combined with that previously obtained for H 2 S and HDS, allows a determination of the molecular constants of hydrogen sulfide. The quadrupole coupling constants for D 2 S are ( eQq j ) 1 10 = 17.83 ± 0.15 kc/sec and ( eQq j ) 1 01 = −10.82 ± 0.28 kc/sec. The components of χ ii = eQ D q ii in its principal axis system are χ xx = 149.0 kc/sec, χ yy = −59.8 kc / sec , and χ zz = −89.2 kc/sec, where the z axis is perpendicular to the plane of the molecule and the x axis is rotated 1°35′ from the DS bond in the direction away from the D-S-D obtuse angle.

Nuclear electric quadrupole moments of Rb from the hyperfine spectrum of RbF

The molecular beam electric resonance technique has been used to examine the hyperfine spectrum of RbF. The Rb nuclear electric quadrupole interaction, the spin-rotation interactions, and tensor and scalar spin-spin interactions have been measured for both Rb isotopes, including their dependence on vibrational and rotational states. Transition frequencies have been determined to a precision of better than 1 Hz in many cases. The magnetic interactions in the two isotopomers are consistent with what is expected from the known masses and magnetic dipole moments. In the case of the Rb nuclear electric quadrupole interaction, adjustments have been made for a small isotopomer shift, and for the ratio of the effective nuclear electric quadrupole moments, Q(87Rb)Q(85Rb) = 0.483 830 1+/-0.000 001 8. The effective quadrupole interaction includes a pseudoquadrupole interaction that may be significant at this level of precision, but cannot be distinguished experimentally.