Stark-zeeman hyperfine structure of H79 Br and H81 Br by molecular-beam electric-resonance spectroscopy

Dabbousi, O.B.; Meerts, W. Leo; Leeuw, F. H. de; Dymanus, A.

doi:10.1016/0301-0104(73)80023-0

Cited by 64 publications

(11 citation statements)

References 13 publications

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“…Inclusion of the relativistic corrections, via the relativistic four-component calculations, improves the agreement with the available experimental values [54][55][56][57][58][59]49 for all molecules. However, one should note that all experimental values, apart from the one for HF, are for the vibrational ground state and are thus not directly comparable with our equilibrium bond length results.…”

Section: Resultsmentioning

confidence: 55%

Relativistic calculations of the rotational g factor of the hydrogen halides and noble gas hydride cations

Enevoldsen

Rasmussen

Sauer

2001

The Journal of Chemical Physics

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Calculations of nuclear quadrupole coupling in noble gas-noble metal fluorides: Interplay of relativistic and electron correlation effectsThe rotational g factors of the hydrogen halides, HX ͑XϭF,Cl,Br,I͒, and noble gas hydride cations, XH ϩ ͑XϭNe,Ar,Kr,Xe͒, have been calculated at the level of the random phase approximation ͑RPA͒ as relativistic four-component linear response functions as well as nonrelativistic linear response functions. In addition, using perturbation theory with the mass-velocity and Darwin operators as perturbations, the relativistic corrections have been estimated as quadratic response functions. It was found that the four-component relativistic calculations give in general a more negative electronic contribution to the rotational g factor than the nonrelativistic calculations with relativistic corrections ranging from 0.2% for HF and NeH ϩ to 2.9% for XeH ϩ and 3.5% for HI. The estimates of the relativistic corrections obtained by perturbation theory with the mass-velocity and Darwin operators are in good agreement with the four-component results for HF, HCl, NeH ϩ , and ArH ϩ , whereas for HI, KrH ϩ , and XeH ϩ they have the wrong sign.

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Section: Resultsmentioning

confidence: 55%

Relativistic calculations of the rotational g factor of the hydrogen halides and noble gas hydride cations

Enevoldsen

Rasmussen

Sauer

2001

The Journal of Chemical Physics

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“…For a two-dimensional isotropic harmonic oscillator, the average angle, (B2), (see Fig. 2) is given by (#2)= , [13] where vb is the bending frequency and is related to the bending force constant, kb, by 1 (kb 1/2 [14] The bending reduced mass, Ab, is taken to be (18) --= + I2+ 1 + 1 2 [15] Ab mor2co mHTc mcLTco cHj…”

Section: Molecular Structurementioning

confidence: 99%

“…The rotational spectrum of OCHBr was measured at [11][12][13][14][15][16][17][18] GHz. From the measured transition frequencies, the rotational constants, centrifugal distortion constants, Br nuclear-quadrupole-coupling constants, and Br spin-rotation constants were obtained and, by using these constants, the vibrationally averaged structure of OCHBr was derived.…”

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confidence: 99%

Microwave spectrum and molecular structure of the carbon monoxide-hydrogen bromide molecular complex

Keenan

Minton

Legon

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

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Rotational spectra have been assigned for five isotopic species of the OC-HBr hydrogen-bonded molecular complex by using pulsed microwave Fourier transform spectroscopy in a Fabry-Perot cavity and a pulsed supersonic'nozzle as the molecular source. The'rotational constants, centrifugal distortion constants, Br nuclear-quadrupole-coupling constants, and Br spin-rotation constants were determined and from them, the vibrationally averaged structure of OCUBr was derived. This structure'is consistent with a linear geometry' at equilibrium and an atomic arrangement'as written above. The intermnolecular potential binding CO to HBr is discussed. A method for the measurement of the molecular properties of transient and other weakly bound molecular species has been developed'by applying Fourier transform techniques in the microwave frequency range (1-4). The method combines the principles of the pulsed Fourier transform microwave technique, a Fabry-Perot cavity, and synchronization of the microwave pulse with a pulsed supersonic-nozzle beam of a gaseous mixture used to generate, in this case, weak van der Waals molecular complexes (5, 6).In this paper, we report rotational assignments for five isotopic species of the weakly bound OCHBr"molecular complex (7). The rotational spectrum of OCHBr was measured at 11-18 GHz. From the measured transition frequencies, the rotational constants, centrifugal distortion constants, Br nuclear-quadrupole-coupling constants, and Br spin-rotation constants were obtained and, by using these constants, the vibrationally averaged structure of OCHBr was derived. OCHBr is nearly linear. We also used the structure and spectroscopic constants of OCHBr to obtain information on the potential that binds CO to HBr. Finally, we compared OCHBr with the ArHBr (8) and KrHBr (8) van der Waals molecules and noted the similarities and differences. EXPERIMENTAL Apparatus. A microwave oscillator at frequency v is phase stabilized to a harmonic of a lower frequency oscillator, which is monitored by using a frequency counter. The primary oscillator is then used to phase stabilize the local oscillator at a frequency of v -30 MHz; this second oscillator is used in the subsequent superheterodyne detection of the signal. The primary microwave source at v is then formed into a pulse by a switch, after which the pulse is impedance matched to a Fabry-Perot cavity. Maximum polarization of the gas is achieved after a ir/2 pulse, T2 >? tp, where T2 is the polarization relaxation time, which is related to the low-power steady-state transition half-width at half-height by AP = 1/ (2irT2), and tp is the microwave pulse length. After polarization of a band of molecular frequencies centered at v, the microwave pulse is switched off, and the pulse dissipates over a relaxation time of rt, the cavity relaxation time. We now require that the molecules maintain their coherent polarization for a period of time long relative to T ; i.e., T2 >> 'r. The T2 >> r, requirement allows the original microwave pulse to die away befor...

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“…As in the cases shown below, both the NQCC at 35 C1 and the dipole moment (1.1085(5) D) were fit to power series in (v +1 /2). Similar studies to the above, for HBr [19,20,21] and DBr [20] [28], Although these correlations are both useful and important, they clearly only work with molecules with very similar bonding systems. In the interhalogens we have effectively a cr-bond and three lone pairs at each end, staggered with respect to each other; i.e.…”

Section: The Hydrogen Halides and Interhalogensmentioning

confidence: 56%

Experimental Gas-phase Halogen Nuclear Quadrupole Coupling Constants; A Review

Palmer

1998

Zeitschrift Für Naturforschung A

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As a preclude to a theoretical study of nuclear quadrupole coupling constants (NQCC), via the electric field gradients at equilibrium, we review the current state of knowledge of gas-phase data for a diverse set of axially symmetric inorganic and organic molecules with symmetries C 3v , C oov , D^ in particular, where the heavy elements are CI, Br and I with C, Si and Ge hydrides. In most of the cases, the latter elements are in an approximately tetrahedral environment.

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Stark-zeeman hyperfine structure of H79 Br and H81 Br by molecular-beam electric-resonance spectroscopy

Cited by 64 publications

References 13 publications

Relativistic calculations of the rotational g factor of the hydrogen halides and noble gas hydride cations

Relativistic calculations of the rotational g factor of the hydrogen halides and noble gas hydride cations

Microwave spectrum and molecular structure of the carbon monoxide-hydrogen bromide molecular complex

Experimental Gas-phase Halogen Nuclear Quadrupole Coupling Constants; A Review

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