Showing papers in "Journal of Molecular Spectroscopy in 1973"

TL;DR: In this article, a nonlinear fitting procedure is presented that employs all measured line positions and iteratively compares their values with those calculated from numerically diagonalized model Hamiltonians with adjustable molecular constants.

TL;DR: In this article, carbon-13 frequency shifts for C 2 H 4, C 2 D 4, and as -C 2 H 2 D 2 have been measured in isotopic solid solutions in crystalline films at 60 K.

TL;DR: In this paper, it was shown that the adiabatic bond lengths of the different isotopes depend linearly on the reciprocals of the masses of the two atoms, with coefficients that are in general distinct.

TL;DR: In this article, the radio-frequency spectra of HF and H35Cl in an external electric and magnetic field are measured using a high-resolution molecular-beam electric-resonance spectrometer.

TL;DR: In this paper, the mass dependence (r m) method was used to estimate the equilibrium structure of a molecule from the zero-point rotational constants of several isotopes. But the main disadvantages of the r m method are that a large number of isotopic molecules may be necessary and that the above equation is not sufficiently accurate for hydrogen-deuterium isotope effects.

TL;DR: In this article, a photolysis of hydrogen and deuterium-containing compounds in an argon matrix correspond well with similar absorptions reported in studies of the trapped products of a glow discharge through Ar:H 2 and Ar:D 2 mixtures.

TL;DR: In this paper, the authors compared two alternative methods for the reduction of observed line positions to spectroscopic constants, i.e., the traditional term value approach and a correlated least-squares fit.

TL;DR: The microwave rotational spectra of five further isotopic species of toluene have been measured as discussed by the authors, and it is demonstrated that the sets of rotational constants obtained from the ground state spectra, A ′ (frame alone), B, C, can be used for the determination of a (partial) substitution structure also in the case of off-axis substituted isotopes.

TL;DR: In this article, the authors developed expressions for computing the centrifugal distortion constants Dv, Hv, and Lv directly from the Rydberg-Klein-Rees rotationless potential of a diatomic molecule.

TL;DR: In this article, a new model Hamiltonian has been developed to study the vibration-inversion-rotation energy levels of ammonia, where the inversion motion is removed from the vibrational problem by allowing the molecular reference configuration to be a function of the large amplitude motion coordinate.

TL;DR: In this article, the Raman spectra of four types of spherical top molecule have been recorded in the vapor phase at temperatures between 20 and 680°C. Fundamental frequencies are reported together with, where possible, the separation of the rotational branch maxima, Δ ν OP, RS of each fundamental.

TL;DR: In this article, the force fields for the in-plane vibrations of benzene and its fluoro derivatives were determined using the overlay technique and convergence on the experimental frequencies was smooth and rapid.

TL;DR: In this article, LCAO-SCF calculations with an extended basis set are used to predict the geometry and various vibrational properties of the hydrogen bonded complex between HCN and HF.

TL;DR: In this article, a vibrational assignment of an absorption at 2717 cm −1 as the NH stretching fundamental of ground-state HNO and of an absorbing at 2043 cm − 1 as the corresponding fundamental of DNO is presented.

TL;DR: In this article, the A 2 Σ + -X 2 Π emission spectrum of HCl+ has been measured and analyzed for four isotopic combinations, and the rotational constants for the v = 0−2 levels of the ground state and for the V = 0-9 levels of excited state have been determined.

TL;DR: In this article, the ground state molecular geometry of CHD 2 CCH was determined from ground state combination differences, from which A 0 values were derived using microwave estimates of B 0 and C 0.

TL;DR: In this paper, the dipole moment was determined from Stark-lobe shifts, μa = 0.640 ± 0.005 D. The high-J transitions were split into multiplets due to the interaction of methyl top internal rotation with the overall molecular rotation; doublets through quintets with the correct nuclear spin weight dependence were observed according to group-theoretical expectations.

TL;DR: In this paper, the ground and excited state dipole moments of D2CO and the excited states dipole moment of H2CO have been determined with an accuracy limited only by the uncertainties in the CO laser frequencies.

TL;DR: In this paper, the microwave spectrum of CF 2 has been extended to include transitions up to J = 40, and a centrifugal distortion analysis has been performed and from the distortion constants, the force field, infrared spectrum, average structure, Coriolis coupling constants, and inertial defect have been calculated.

TL;DR: In this article, the fluorescence spectrum of NO2 excited by a single mode argon-ion laser was studied at a spectral resolution of 0.1 cm−1, and the vibrational and rotational parameters of the ground electronic state and the rotational constants of the B2 vibronic state were obtained.

TL;DR: In this paper, the rotational structure of the ν 1, ν 3, 2 ν 2, 2 ǫ 2, ν 0, ξ 0, ξ 1 + ξ 2, and ν √ ν − 2 +ǫ 3 bands of water vapor has been recorded using a high resolution vacuum infrared spectrograph.

TL;DR: The Coriolis resonance between the v 1 = 1 and v 3 = 1 vibrational states has perturbed very much the spectra of these states and gave a very accurate value of the difference between the ν 1 and ν 3 fundamental frequencies as discussed by the authors.

TL;DR: In this paper, an expression for the Hamiltonian of a vibrating-rotating-inverting formaldehyde molecule is derived by using one curvilinear coordinate corresponding to the angle between the CO bond and the bisector of the angle HĈH.

TL;DR: In this article, a treatment of the intensities of vibration rotation bands for polyatomic molecules is given using a method involving contact transformations, leading to explicit expressions relating the observed intensities to the anharmonic coefficients of the expansions of the potential energy and the dipole moment.

TL;DR: In this article, a simple and rapid method for the determination of the RKR turning points from the vibrational term values and rotational constants is presented. Butler et al. presented a numerical procedure for the computation of these constants from the turning points.

TL;DR: In this paper, the symmetry properties of the rotational and torsional levels of two identical XY2 groups connected by a symmetrical linear chain of atoms, with an arbitrary barrier to internal rotation, are investigated.

TL;DR: In this article, the authors measured the infrared spectra of CH 2 F 2 and CD 2F 2 under a medium resolution, and the assignment of the vibration-rotation bands of CD 2 F2 fundamentals has been given.

TL;DR: In this article, the ground state of CH4 has been observed by infrared-radio frequency double resonance using the 3.39 μ HeNe laser line, and the transition frequencies are 423.02 ± 0.02 MHz and 1246.55 ± 0.02 MHz, respectively.