FTIR spectra and rovibrational analysis of parallel bands involving the ν1, ν2, and ν3 levels of natural and monoisotopic FClO3

Fourier Transform infrared spectra of gaseous natural FClO₃ and monoisotopic F³⁵ClO₃ have been recorded at 293 and 225 K with a resolution of 0.04 cm⁻¹. Rotational J structure and, in part, K structure were resolved for the parallel fundamentals, combination bands, and overtones ν₁, ν₂, ν₃, ν₁ + ν₂, ν₁ + ν₃, ν₂ + ν₃, 2ν₁, 2ν₂, and 2ν₃. Band origins ν₀, anharmonicity constants χ_ij, and vibration-rotation interaction constants α_i^A and α_i^B have been determined. For F³⁵ClO₃, ν₀ values are ν₁ = 1063.238(6), ν₂ = 716.814(6), and ν₃ = 549.877(3) cm⁻¹. No perturbation was found at the present level of accuracy.     

Beta decay of polarized Λ hyperons III. Correlations in the Λ centre-of-mass system and the proton recoil spectrum

From the analysis of 817 kinematically resonstructed beta decay events of polarized Λ hyperons for the coefficient α_ν of the neutrino correlation with respect to the Λ spin, α_ν = 0.89 ± 0.08, for the coefficient α_T of the T-odd correlation σ_Λ(p_e × p_ν), α_T = ?0.14 ± 0.13. The proton recoil spectrum yields …g₁/f₁… = 0.64 ± 0.06.     

Analysis of the ν1 band of CH3I

The rotational structure of the infrared band ν₁ of CH₃I has been studied at a resolution of 0.04 cm^?1 using a grating spectrometer. In the analysis including 470 lines a resonance, explained to be caused by ν₂ + 2ν₆^±2, has been taken into account. The molecular constants derived include, e.g., α₁^A = 0.051129(14) cm^?1 and α₁^B = 0.0983(9) × 10^?3 cm^?1.     

The ν3 band of CD3I around 500 cm−1

The region of the lowest fundamental band ν₃ of CD₃I around 500 cm^?1 is studied at a resolution of 0.015 cm^?1. The K structure in the parallel band ν₃ is resolved for K = 6 – 14. Molecular constants for the ν₃ level are derived, including α₃^A = 3.055(13) × 10^?3 cm^?1. The “hot” band 2ν₃-ν₃ is also investigated.     

The microwave spectra and vibration-rotation interaction constants for CD3I in the excited vibrational states

The microwave spectra in the J = 1 → 3 region for CD₃I has been observed and six excited vibrational states assigned. The vibration rotation interaction constants, α^B and nuclear quadrupole coupling constants, eQq, have been determined for the states: ν₂, ν₃, ν₅, ν₆, 2ν₃, and ν₃ + ν₆. For the degenerate vibrational states, the l type doubling constants, q_t were determined.     

High-resolution vibration-rotation spectroscopy of fluoroform-d

The vibration-rotation spectrum of the ν₂ and ν₅ fundamentals of CDF₃ have been recorded using a Nicolet 7199 Fourier transform infrared spectrometer; in addition the Q branch and several subbands of each of these transitions have been investigated using a tunable semiconductor diode laser spectrometer. The Q branch and the K structure in several P(J) and R(J) subbands of ν₂, and in several Q branches of ν₅, are resolved and assigned for the first time. Constants derived for these bands are (in cm^?1) ν₂ = 1111.1823₆, B₂ = 0.32928₂, A₂ = 0.18872₂, α₂^B = 16.44₅ × 10^?4, α₂^B ? α₂^A = 12.43₅ × 10^?4, D₀^j = 3.7₃ × 10^?7, D₂^J = 4.8₃ × 10^?7; ν₅ = 975.39₁, B₅ = 0.33062, A₅ = 0.18887, α₅^B = 2.83₁ × 10^?4, α₅^A = 2.4₃ × 10^?4, ζ₅ = 0.736, D₅^J ? D₀^J = 1.2₂ × 10^?8. Some of these constants are nearly 100 times more precise than those reported in previous work.     

The bending vibration bands ν4 and ν5 of HCCI

The bending vibration bands ν₄ and ν₅ of HCCI were studied. From the observed rotational structure the rotational constant B₀ and the centrifugal distortion constant D₀ were obtained. The results were B₀ = 0.105968(7) cm^?1 and D₀ = 1.96(7) × 10^?8 cm^?1 from ν₄ and B₀ = 0.105948(8) cm^?1 and D₀ = 1.96(11) × 10^?8 cm^?1 from ν₅. The structure of the hot bands 2ν₅(Δ) ← ν₅(Π) and 3ν₅(φ) ← 2ν₅(Δ) was also resolved and hence the values α₅ = ?3.033(8) × 10^?4 cm^?1 and q₅ = 9.3(3) × 10^?5 cm^?1 could be derived. The other most intense hot bands following ν₅ could be explained in terms of the Fermi diads $\text{ν}{}_3\text{2ν}{}_5{}^0$ and $\text{ν}{}_3\text{+}\text{ν}{}_5{}^{\mathrm{\pm 1}}\text{3ν}{}_5{}^{\mathrm{\pm 1}}$. Of the numerous hot bands accompanying ν₄, only those between different excited states of ν₄ could be assigned. Then estimates for α₄ and q₄ were also obtained. In addition, several vibrational constants were derived.     

Inverse Raman spectrum of the ν1-fundamental of CF4

We have obtained fully resolved spectra of the ν₁ (Q-branch) band of CF₄ at a pressure of 4 Torr using a variation of stimulated Raman spectroscopy. With an experimental resolution of ≤0.004 cm^?1, no detectable tensor splitting of the rotational levels exists up to J = 55. The spectrum is readily fit with a band origin α = 909.0720 cm^?1 and a single rotational term β ? β₀ = ?3.417 × 10^?1cm^?1. We have also observed an underlying hot band, which we tentatively assign as the ν₁ + ν₂ ← ν₂ transition, with α′ = 909.1997 cm^?1 and (β ? β₀)′ = ?3.405 × 10^?4cm^?1.     

High-resolution stimulated Raman gain spectrum of the ν1 band of SF6

We report rotationally resolved stimulated Raman gain spectra of the ν₁ band of SF₆. The fundamental band exhibits a rigid-rotor type spectrum that is readily fit with a band origin of Δα = 774.5445 and a single rotational term Δβ = ?1.10376 × 10^?4 cm^?1. We also observed and analyzed the ν₁ + ν₆ hotband with band origin at 774.1820 cm^?1. With an experimental resolution of 0.0024 cm^?1 there is no evidence for centrifugal distortion or tensor splitting in either band, although the ν₁ + ν₆ band does exhibit first-order Coriolis splitting as expected.     

Vibrational Raman spectrum of SF6

The Raman active fundamentals and the first overtone of the inactive fundamental of SF₆ gas were measured with sufficient resolution to observe the shapes of the Q branches and to resolve some of the hot-band Q branches. The values in wavenumber units (cm^?1 of the estimated band origins are: ν₁ = 774.4, ν₂ = 643.5, ν₅ = 524.0, and 2ν₆ = 693.8. By combining our value of ν₂ + ν₆ ? ν₆ with the value for the ν₂ + ν₆ infrared band, we found ν₆ = 347.8 cm^?1. Several anharmonicity constants are also calculated.     

Fourier transform spectroscopy on the 3ν2, 2ν2 + ν6 and ν3 + ν5 bands of H2CO

Fourier transform spectra covering the range from 1500 to 5400 cm^?1 with 0.02-cm^?1 resolution have been obtained for formaldehyde. A study of the region above 4000 cm^?1 has yielded rotational constants and other asymmetric rotor parameters for three bands: 3ν₂ (ν₀ = 5177.7611 ± 0.0005 cm^?1)2ν₂ + ν₆ (ν₀ = 4734.193 ± 0.004 cm^?1), and ν₃ + ν₅ (ν₀ = 4335.102 ± 0.001 cm^?1). An analysis of the A-type Coriolis interaction between the 2ν₂ + ν₆ state and the unobserved 2ν₂ + ν₄ state has yielded partially deperturbed rotational constants for the 2ν₂ + ν₆ state. Vibration-rotation interaction constants have been obtained for the ν₂ and ν₆ normal modes by combining the present results with those of previous workers.     

Vibration-rotation spectra of CD3CN

Rotational structure in two parallel and five perpendicular bands of CD₃CN is fully analyzed at a resolution of 0.2–0.3 cm^?1. The unresolved contour of the ν₈ fundamental is reproduced by contour simulation and a value of ζ8^z determined. Strong A₁-E Coriolis interactions between the close lying fundamentals ν₃ and ν₆, and ν₄ and ν₇ are interpreted by means of computer contour simulations. Marked localized perturbations in the perpendicular ν₅ and ν₅ + ν₆ bands are analyzed and arise through Fermi resonance interactions, most probably with ν₆ + ν₇ + ν₈ and 2ν₃ + ν₆, respectively. A value of A for the ground state is calculated through use of the rotational data for ν₅, ν₆, ν₅ + ν₆, and customary approximations. In conjunction with the microwave B₀ value, it is consistent with a CD₃ group geometry of $\text{r}{}_0\text{= 1.096}\text{A}\text{?}$, α₀(DCD) = 108° 56′.     

Vibrational spectra and force constants of symmetric tops: Rotational analysis of ν3 and several hot bands of H3SiI near 360 cm−1

The gas-phase infrared spectrum of natural H₃SiI has been recorded in the ν₃ range between 390 and 320 cm^?1 with a resolution of 0.04 cm^?1. The fundamental ν₃ and the three most intense “hot” bands 2ν₃ ? ν₃, 3ν₃ ? 2ν₃, and ν₃ + ν₆ ? ν₆ have been detected. The molecular parameters ν₀, x₃₃, x₃₆, B″, α₃^A, α₃^B, and D_J were determined by a least-squares analysis of the P and R branches resolved into J lines (J ≤ 110) and by a band contour simulation procedure, respectively.     

On the Deser,Gilbert, Sudarshan representation for functions Wi(ν, q2)(i = 1, 2) describing the electroproduction process

The Deser, Gilbert, Sudarshan representation (D.G.S.R.) for the functions W_i(ν, q²) (i = 1,2) is considered as equations determining spectral functions h_i(a, α) via the values W_i(ν, q²) in the physical region of the electroproduction channel. It is shown that if W_i(ν, q²) obey the microcausality and spectrality conditions, then the equations for h_i(a, α) have solutions in the class of Schwartz temperated distributions and thereby the D.G.S.R. is proved. Formulae are obtained expressing spectral functions in the D.G.S.R. through the values of functions W_i(ν, q²) in the physical region of the electroproduction channel.     

Microwave spectrum of nitrogen dioxide in excited vibrational states—Equilibrium structure

Microwave spectra were observed for ¹⁴NO₂ in the vibrationally excited ν₁, ν₂, ν₃, and 2ν₂ states, as well as for ¹⁵NO₂ in the ν₁ and ν₂ states. The rotational constants, spin-rotation coupling constants and hyperfine interaction constants were precisely determined. Second-order change of the spin-rotation coupling constants with respect to the bending vibrational quantum number v₂ was also determined. Combined use of the rotational constants obtained by the present microwave investigation and those reported in high-resolution infrared spectroscopic studies leads to the determination of all the vibration-rotation interaction constants α_s and γ_ss′ and the equilibrium structure of nitrogen dioxide, $\text{r}{}_{\mathrm{<mtext>e</mtext>}}\text{(}\text{N}\text{O) = 1.19389 ± 0.00004}\text{A}\text{?}$ and θ_e (ONO) = 133°51.4′ ± 0.2′, in the second-order approximation with respect to the vibrational quantum numbers.     

Analysis of the ν6(A″2) band of cyclopropane-d6 recorded under high resolution

The parallel band ν₆(A″₂) of C₃D₆ near 2336 cm^?1 has been studied with high resolution (Δν = 0.020 – 0.024 cm^?1) in the infrared. The band has been analyzed using standard techniques and the following parameters have been determined: B″ = 0.461388(20) cm^?1, D″_J = 3.83(17) × 10^?7 cm^?1, ν₀ = 2336.764(2) cm^?1, α^B = (B″ ? B′) = 8.823(12) × 10^?4 cm^?1, β^J = (D″_J ? D′_J) = 0, and α^C = (C″ ? C′) = 4.5(5) × 10^?4 cm^?1.     

Diode laser spectroscopy of several bands of hydroxylamine

Diode laser spectroscopy has been carried out on the ν₅ (1115 cm⁻¹) and ν₆ (895 cm⁻¹) fundamentals, the 2ν₉ overtone, the 3ν₉-ν₉ hot band, and the ν₅-ν₉ difference band (all near 700 cm⁻¹) of hydroxylamine (NH₂OH). (ν₅ = NH₂ wag, ν₆ = NO stretch, and ν₉ = OH torsion.) Transition frequencies were determined with a nominal accuracy of ±0.001 cm⁻¹. Accurate molecular parameters were determined for the ground state, v₆ = 1, v₉ = 1, and v₉ = 2. The v₅ = 1 and v₉ = 3 states were perturbed by a Coriolis interaction with each other and possibly with a third state. In these cases effective rotational and distortion constants were determined together with empirical perturbation parameters. The data obtained on ν₅ and ν₆ enabled assignments of the transitions involved in the optically pumped hydroxylamine FIR laser to be made.     

Radiative corrections to νμ + N → μ− + X and their effect on the determination of ϱ2 and sin2θW

We study the O(α) corrections to σ_T(ν_μ + N → μ^? + X). The coefficient of the leading O(αln m_Z) contribution is given by a general theorem as in the case of β decay, while the energy scale accompanying m_Z in the argument of the logarithm as well as mass singularities and non-logarithmic terms are obtained by a detailed quark-parton model calculation. The effect of muon mass singularities, when there is an experimental vut in the low range of the y distribution, is also investigated. Combining these new results with our previous analysis of σ_T(ν_μ + N → ν_μ + X), we calculate theSU(2)_L × U(1) parameter ?_(νμ;h)² and evaluate the effect of the O(α) corrections on the determination of sin²θ_W^exp from deep inelastic ν_μ scattering. Applying these corrections to existing data, we obtain the weigthed average sin²θ_W^exp = 0.216 ± 0.010 ± 0.004. This value when used in conjuction with our previous analysis of the W^± and Z⁰ masses provides the predictions m_W = 83.0_?2.8^+3.0 GeV and m_Z = 93.8_?2.4^+2.5 GeV. For the weak interaction angle defined by modified minimal subtraction we find sin²θ_W(m_W) = 0.215 ± 0.010 ± 0.004, which is in very good agreement with the SU(5) prediction we have recently given.     

Diode laser spectroscopy of the ν4 band of 13CD3I

The ν₄ band of ¹³CD₃I was recorded under Doppler-limited resolution in the region 2260–2296 cm^?1 using a tunable diode laser spectrometer. About 400 P and R transitions from KΔK = ?6 to KΔK = +6 were assigned, and seven Q branches from KΔK = ?4 to KΔK = +2 were partly resolved. Molecular constants for the ν₄ level were derived, including q₄ and η parameters. The ν₁ band of ¹³CD₃I was also recorded under a resolution of 0.05 cm^?1 using a grating spectrometer. The band origin as well as α₁^A and α₁^B constants were obtained.     

The ν2 fundamental band of H2CO

The ν₂ fundamental band of H₂CO has been studied using a combination of sub-Doppler laser Stark spectroscopy and Doppler-limited Fourier transform spectroscopy. A combined analysis of the Stark and Fourier infrared data together with previous microwave data on the ν₂ = 1 state yielded improved molecular parameters for formaldehyde, including the excited state dipole moment. A small perturbation was noted at K′_a = 7 which may be ascribed to a ΔK_a = 2 interaction with the v₃ = 1 state. Precise treatments of ν₂ with K′_a > 6 will thus require a combined analysis taking into account Coriolis interactions among ν₄, ν₆, ν₃, and ν₂.