Determination of A0 for CH335Cl and CH337Cl from the ν4 infrared and Raman bands

The ν₄ infrared and Raman bands of CH₃Cl were analyzed simultaneously. A direct fit yielded a complete set of constants for CH₃³⁵Cl, including A₀ = 5.20530 ± 0.00010 cm^?1 and D_K = (8.85 ± 0.13) × 10^?5cm^?1. For CH₃³⁷Cl an incomplete set of constants was obtained from the infrared band, and A₀ = 5.2182 ± 0.0010 cm^?1 was estimated by curve fitting of the Raman spectrum. The resulting equilibrium structure is $\text{r(}\text{CH) = 1.0854 ± 0.0005}\text{A}\text{?}$, $\text{r(}\text{CCl) = 1.7760 ± 0.0003}\text{A}\text{?}$, and <(HCH) = 110°.35 ± 0°.05.     

Determination of A0 from the ν4 Raman band of CD3Br

The principles and methods of determining A₀ from the Raman spectra of degenerate fundamentals of C_3v molecules are outlined, and applied to the ν₄ band of CD₃Br to yield a value of A₀ = 2.6004 ± 0.0010 cm^?1.     

Magnetic susceptibilities of polycrystalline samples of the compounds ANiCl3 (A = RB,NH4, Tl,Cs) and ANiBr3 (A = Rb,Cs)

The susceptibilities of polycrystalline samples of various antiferromagnetic linear-chain compounds ANiX₃ (A =Tl, NH₄, Rb, Cs and X = Cl, Br) have been measured in the temperature region 2–200 °K. The results, amongst which the already known data for RbNiCl₃ and CsNiCl₃, are interpreted in terms of a theory, developed by Weng, for antiferromagnetic Heisenberg linear-chain systems with spin S = 1. By means of Oguchi's Green function theory and the experimentally determined transition temperatures T_N the order of magnitude of the ratio between inter- and intra-chain interaction is obtained.     

Determination of A0 for the symmetric top molecules

A new method for the determination of the constant A₀ in symmetric top molecules is proposed. This method utilizes the data for the overtone bands of a doubly degenerate vibration of symmetry species E_1u. Transitions necessary for the determination of A₀ have been indicated for all symmetric top symmetry groups. The precision of A₀ values determined according to the method suggested is also discussed.     

High precision spectrum of N2O at 4.5 μm and determination of molecular constants for the ν3 and the (ν2 + ν3 − ν2) bands

A high precision wavenumber calibration has been achieved for the spectrum of N₂O at 4.5 μm. The values of the wavenumbers are reported for the (00°1-00°0) and for the (01¹1-01¹0) transitions. A new set of molecular constants is given for the upper and lower levels of these two transitions. In particular, the value of the H constant for the ground state (?2.02 ± 0.4) × 10^?13 cm^?1 determined in this work is significantly different from previous results.     

A3-Weight multiplicity formula

We write down an explicite formula for the multiplicity of a weight in an arbitrary irreducible module of the classical algebra A₃. For this purpose we first derive a reccurrence relation between the multiplicities of the weights in A_a and A_s?1.     

Measurements of analyzing powers Ay, Axx, Ayy and Axz in dp elastic scattering at Ed = 56 MeV

The differential cross section and all components of the analyzing powers A_y, A_xx, A_yy and A_xz have been measured in dp elastic scattering at 56 MeV. This is the first measurement of A_xz in the cyclotron energy region. A_xz has been measured with the beam polarized in the horizontal plane using the polarization tagging method. Faddeev calculations have been performed for four cases of the NN interaction. The Coulomb correction gave smaller effects at the present energy than at lower energies. Three of them reproduce the experimental data well. The agreement between the calculations and data for A_xz was better than that reported at lower energy. The deuteron asymptotic D- to S-state ratio has been obtained and is consistent within the limits of uncertainty with previously obtained values.     

A series of new compounds A3+Fe2 O4 (A = Ho,Er, Tm,Yb, and Lu)

A series of new compounds A Fe₂ O₄ (A = Ho, Er, Tm, Yb, and Lu) have been successfully synthesized under the lower oxygen partial pressures at 1200°C and their unit cell dimensions were determined.     

Determination of A0 of CH3Br from its Raman spectrum

A value of A₀ = 5.1800 ± 0.0010 cm^?1 for CH₃Br has been determined from an analysis of the ν₄ Raman band, based both on a direct fit of Q-branch frequencies and on ground state combination differences. The constants ν₄, (Aζ)₄, η₄₄, and A_e = 5.2442 ± 0.0015 cm^?1 were also determined. The equilibrium distance of the H atoms from the figure axis is calculated as 0.32077 ± 0.00005 Å. All the fundamental Raman bands of CH₃Br were observed, and experimental results for the ν₁, ν₂ and ν₅ bands are included.     

The high-resolution infrared spectrum of ethane-1,1,1-D3 rovibration analyses of the pseudoperpendicular A1A2ν9 + ν10 band and the parallel ν3 + ν4 and ν5 bands

A complete vibration-rotation analysis was made of the A₁A₂ combination band ν₉ + ν₁₀ of CH₃CD₃ at 2582 cm^?1. This band exhibits pseudoperpendicular structure due to the large effective Coriolis interaction constant (ζ ≈ 0.7), which couples the almost degenerate A₁ and A₂ vibrational components for all nonzero values of the rotational quantum number K, and gives a subband Q-branch spacing of 2.5 cm^?1. The location of the band center is assisted through an interruption of the perpendicular-like structure, since both K = 0 Q branches are forbidden by the vibrational and rotational selection rules. The conventional A₁ parallel bands ν₃ + ν₄ at 2507 cm^?1 and ν₅ (CC stretch) at 905 cm^?1 were also analyzed. For ν₅, a combination of numerical analysis and band contour simulation was used to determine a set of upper-state rotation parameters. Combination of the present results with previous data for ν₉ and 2ν₃ permits rotational parameters to be derived for the ν₄ and ν₁₀ fundamentals of CH₃CD₃. Neither of these fundamentals are amenable to straightforward analysis, both being very weak in the infrared and overlaid by the intense ν₁₁ fundamental.     

The analyzing power Aγ(θ) for the elastic scattering of 12 MeV neutrons from deuterons

The analyzing power A_γ(θ) was obtained at 10° intervals between 30° (lab) to 120° (lab) for ²H(n, n)²H at 12.0 MeV. The polarized neutron beam employed in the measurement was obtained by using neutrons emitted at 0° from the polarization transfer reaction ${}^2\text{H}\text{(}\text{d}\text{,}\text{n}\text{)}{}^3\text{He}$. The accuracy in the A_γ(θ) values that was achieved ranged from ± 0.006 to ± 0.013. Comparison of the data to A_γ(θ) results obtained at 12 MeV for the charge symmetric reaction ²H(p, p)²H shows that the two A_γ(θ) distributions are equal to within the above accuracy.     

Lattice vibration analysis of cryolite A3B′X6 and elpasolite A3BB′X6 compounds. A force constant calculation of Sr2ZnTeO6

A normal coordinate treatment of crystals with general formula A₃B′X₆ and A₂BB′X₆ with cubic structure (space group F_m3m) is made with the G-F matrix method. A modified valence force field is assumed to give a set of ten force constants for calculating all fundamental vibrations in the k = 0 approximation.     

Measurement of the spin correlation parameter Aoonn and of the analyzing power for pp elastic scattering in the energy range from 0.5 to 0.8 GeV

The spin correlation parameter A_oonn and the analyzing powers A_oono and A_ooon were measured simultaneously, in the energy range 0.5–0.8 GeV and in the angular region 40°–80° CM. The experiment used the polarized proton beam of SATURNE II and the Saclay frozen spin polarized target.     

The propagator in the A0 = 0 gauge

We compute the Wilson loop in the A₀ = 0 gauge for abelian and non-abelian theories. We find to fourth order that only two choices for the longitudinal propagator are consistent with the results obtained in the Feynman and Coulomb gauges. In particular the principal value presciption does not work.     

The ν2 and ν4 bands of AsH3

The infrared absorption of arsine, AsH₃, between 750 and 1200 cm^?1 has been recorded at a resolution of 0.006 cm^?1. Altogether 2419 transitions, including nearly 700 “perturbation allowed” transitions with Δ∥k ? l∥ = ±3, ±6, and ±9, have been assigned to the ν₂(A₁) and ν₄(E) bands. Splitting of the transitions for K″ = 3, 6, and 9 was also observed. To fit the rotational pattern of the v₂ = 1 and v₄ = 1 vibrational states up to J = 21, all the experimental data were analyzed simultaneously on the basis of a rovibrational Hamiltonian which took into account the Coriolis interaction between ν₂ and ν₄ and also included several essential resonances within them. The derived set of 38 significant spectroscopic parameters reproduced the 2328 transition wavenumbers retained in the final fit within the accuracy of the experimental measurements.     

Tunable laser study of the ν10 + ν11 band of cyclopropane

Diode laser measurements of the ν₁₀ + ν₁₁ (l_tot = ±2) perpendicular band of cyclopropane have led to the assignments of roughly 600 lines in the 1880–1920-cm^?1 region. Most of the spectra were recorded and stored in digital form using a rapid-scan mode of operating the laser. These spectra were calibrated, with the aid of a computer, by reference to the R lines of the ν₁ + ν₂ band of N₂O. The ground state constants we obtained are (in cm^?1) B = 0.670240 ± 2.4 × 10^?5, D_J = (1.090 ± 0.054) × 10^?6, D_JK = (?1.29 ± 0.19) × 10^?6, D_K = (0.2 ± 1.1) × 10^?6. The excited state levels are perturbed at large J values, presumably by Coriolis couplings between the active E′(l_tot = ±2) and the inactive A′(l_tot = 0) states. Effective values for the excited state constants were obtained by considering only the J < 15 levels. The A₁-A₂ splittings in the K′ = 1 excited states were observed to vary as q_effJ(J + 1), with q_eff = (2.17 ± 0.17) × 10^?4 cm^?1.     

Non-classical effects in multiparticle propagation through a nucleus and the π→A1 problem

The effective cross-section for the propagation of n independent particles through a nucleus can be appreciably less than the sum of their individual cross-sections. Applied to the A₁ problem we conclude that the A₁ is not an unbound ?π (Deck mechanism) or 3π system.     

Simultaneous analysis of the ν1, ν4, 2ν2, ν2 + ν5, and 2ν5 infrared bands of 12CH3F

The Fourier-transform spectrum of CH₃F from 2800 to 3100 cm^?1, obtained by Guelachvili in Orsay at a resolution of about 0.003 cm^?1, was analyzed. The effective Hamiltonian used contained all symmetry allowed interactions up to second order in the Amat-Nielsen classification, together with selected third-order terms, amongst the set of nine vibrational basis functions represented by the states ν₁(A₁), ν₄(E), 2ν₂(A₁), ν₂ + ν₅(E), 2ν₅⁰(A₁), and 2ν₅^±2(E). A number of strong Fermi and Coriolis resonances are involved. The vibrational Hamiltonian matrix was not factorized beyond the requirements of symmetry. A total of 59 molecular parameters were refined in a simultaneous least-squares analysis to over 1500 upper-state energy levels for J ≤ 20 with a standard deviation of 0.013 cm^?1. Although the standard deviation remains an order of magnitude greater than the precision of the measurements, this work breaks new ground in the simultaneous analysis of interacting symmetric top vibrational levels, in terms of the number of interacting vibrational states and the number of parameters in the Hamiltonian.     

Analysis of the ν3, A-type band of C2H3D

The ν₃, A-type band of C₂H₃D centered at 1288.780 cm^?1 has been analyzed up to J = 33 and K_a = 15. The spectral range from 1351 to 1235 cm^?1 was recorded with a grill-spectrometer “type Girard” and with a resolution of 0.06 cm^?1, and a wavenumber precision of about 2 × 10^?3 cm^?1. From 787 identified transitions it was possible to calculate the rotational energies in the ν₃ excited state, and to refine the corresponding set of parameters.     

The analyzing power Ay(θ) for the 9Be(p, n)9B reaction from 8 TO 15 MeV

The analyzing power A_y(θ) for the ⁹Be(p, n)⁹B reaction was measured at seven energies between 8.1 to 15.0 MeV for reaction angles between 0° and 100° (c.m.). The A_y(θ) values are predominantly negative and exhibit a smooth variation with energy. The significance of these results in Lane optical- model calculations for the ⁹Be + nucleon system and in comparisons between the observables P^y(θ) and A_y(θ) is indicated.