The ultraviolet emission spectrum of LaO

The ultraviolet emission spectrum of LaO, obtained under improved experimental conditions, has been reexamined. The high-resolution rotational analysis of the 0, 0 and 0, 1 F²Σ⁺ → X²Σ⁺ and 0, 0 D²Σ⁺ → X²Σ⁺ bands shows that the two excited electronic states F²Σ⁺ and D²Σ⁺ exhibit characteristic features of a b_βJ coupling scheme. A ligand field multiconfigurational calculation shows that these states arise mainly from the 7s and 8s configurations and gives theoretical support to the observed coupling case.     

远紫外及真空紫外反射率测量的研究

本文报道了一种采用成象式折叠腔测量真空紫外区域绝对反射率的方法,测量准确度为±5×10~(-3),精密度为±5×10~(-4).     

Reexamination of the vacuum ultraviolet emission spectrum of CO in the 950–1200 Å region

New spectrograms of CO below 1200 Å reveal that emission bands terminating on the high energy $\text{E}{}_0{}^1\text{Σ}{}^{\mathrm{+}}$ and ¹Π states plus most of the previously reported unidentified emission bands of CO actually originate from molecular nitrogen. Four new emission band systems in CO, tentatively identified as V¹Π-X¹Σ⁺, W¹Π-X¹Σ⁺, Y¹Σ⁺-X¹Σ⁺, and Z¹Σ⁺-X¹Σ⁺, have been observed. The corresponding T_v0′s are 98917, 102804, 99963, and 105724 cm^?1, respectively.     

The spectrum of SiO in the vacuum ultraviolet region

The absorption spectrum of SiO has been photographed at high resolution in the region 1200–1500 Å. Several new electronic states have been observed, valence states as well as Rydberg states. Tables of the molecular constants of all the known states of SiO are given. Due to interactions between the electronic states, the constants of all states analyzed vary irregularly. From the Rydberg series a value of the ionization potential has been derived. It agrees with the value earlier reported, 11.6 ± 0.2 eV.     

The ultraviolet absorption spectrum of thioformaldehyde

The spectra of H₂CS and D₂CS were surveyed over the wavelength region from 230 to 180 nm and four distinct absorptions were identified. These are assigned to transitions from the $\text{X}\text{?}{}^1\text{A}{}_1$ ground state to the $\text{B}\text{?}{}^1\text{A}{}_1\text{(π, π}{}^1\text{)}$, $\text{C}\text{?}{}^1\text{B}{}_2\text{(n, 3s)}$, $\text{D}\text{?}{}^1\text{A}{}_1\text{(n, 3p}{}_{\mathrm{y}}\text{)}$, and $\text{E}\text{?}{}^1\text{B}{}_2\text{(n, 3p}{}_{\mathrm{z}}\text{)}$ electronic states. A vibrational and rotational analysis of the second system was undertaken. The results indicate that the molecule is planar in the $\text{C}\text{?}{}^1\text{B}{}_2\text{(n, 3s)}$ state and that while the CH and CS bond lengths remain near their ground-state values, the HCH angle increases substantially.     

The emission spectrum of HgI

The ultraviolet emission systems of HgI—C → X, D → X, F₃ → X, G → X, and H → X—are photographed and analyzed using tesla-discharge sources containing isotopically pure ²⁰⁰Hg. The previous assignment for F₃ → X is revised, the main change being a decrease by 3 units in the v″ numbering. Results for the other systems corroborate the existing interpretations, except that for C → X there are prominent intensity gaps in the unresolved rotational structure of the bands, not reported previously for “natural” HgI spectra. These gaps are attributed to perturbations of the C state by high levels (v ≈ 90) of the B state. The data for these systems are combined with existing B → X data for ²⁰⁰Hg¹²⁷I and ²⁰⁰Hg¹²⁹I and fitted simultaneously to yield optimal vibrational parameters for all states. In this analysis the X state is fitted to a mixed representation—a polynomial in ( ) for v ≤ 20 and a near-dissociation expansion for v ≥ 20, with G_v and its first derivative constrained to be continuous at v = 20. The revised estimate of _e for X is 2800 ± 40 cm⁻¹. The recommended vibrational parameters (cm⁻¹) for v ≤ 20 are ω_e = 125.41, ω_ex_e = 1.009, ω_ey_e = −0.0159.     

The emission spectrum of the NS molecule

The investigation of the emission spectrum of NS molecule has been carried out by using a Littrow-type quartz spectrograph and a two meter normal incidence type vacuum spectrograph. Theγ-system (² σ-² π), in which only the bands havingv′=0 and 1 were known previously, has been extended tov′=4. TheδG values of the upper state do not show much regularity indicating some perturbation in this state. The vibrational constants for theΒ-system (² δ-² π) have also been modified slightly by observing more bands for this system. Four new systems, all of which have the ground state as their common lower state, have been observed in the ultraviolet and the vacuum ultraviolet regions.     

The vacuum ultraviolet absorption spectrum of ClO

The flash photolysis of ClO₂ has yielded a new absorption spectrum of ClO in the vacuum ultraviolet. Six electronic transitions have been assigned and vibrational constants for the upper states are given. All of the transitions are Rydberg in nature. The first four of these transitions are thought to be ²Σ ← X²Π_i from which a spin-orbit coupling constant A = ?318 ± 5 cm^?1 is obtained for the ground state.Hot bands in three of the above systems of ClO have been observed in absorption. This has enabled the direct measurement of the ground state vibrational constant ($\text{Δ}\text{G}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{″ = 845 ± 4}\text{cm}{}^{\mathrm{?1}}$; ω_e″ = 859 cm^?1) for the first time.Extinction coefficients for a number of the ClO transitions have been measured.     

The visible emission spectrum of iodine

The emission spectrum of iodine has been photographed in the visible region at high resolution, and 16 bands of the $\text{B[0}{}^{\mathrm{+}}\text{u(}{}^3\text{Π}\text{)] → X[0}{}^{\mathrm{+}}\text{g(}{}^1\text{Σ}\text{)]}$ system have been rotationall analyzed. Centrifugal distortion constants for the B state are calculated from the empirical (RKR) potential curve using a method which employs semiclassical phase integrals. The results of the rotational analysis are processed together with earlier results to yield improved spectroscopic parameters for the B state, valid for 3 < v′ < 40.     

The electronic emission spectrum of SiB

The gas phase spectrum of the silicon boride radical has been observed for the first time. Two electronic transitions were observed in emission from a corona excited supersonic expansion source. The D⁴Σ⁻-X⁴Σ⁻ system consists of emission from v′ = 0 to v″ = 0-3, while the A⁴Π-X⁴Σ⁻ system consists of numerous bands with v′ = 0-5 and v″ = 0-11, although only the strong 0-0 and 0-1 bands have been analyzed so far.     

The vacuum ultraviolet absorption spectrum of diatomic calcium

Calcium granules (99.5%) have been heated to 615°C in a tantalum furnace and the absorption spectrum has been observed on the SA 61 beam line of SUFERACO (Orsay) using a 3-metre Balzers monochromator down to the -LiF cut-off (1015 Å). An intense Rydberg series has been observed between 1900 and 1500 Å. This series extends from n = 5 to n = 12 and gives the ionization potential at 63068 cm^?1 (1585.6 Å) or 7.819eV and the quantum defect δ = 1.73.     

Spectral thermal emission of LiF slabs in the far infrared

The spectral thermal emission of LiF slabs on metallic substrate is measured for different polarizations in the wavelength region between 30 μm and 130 μm at a temperature of 523 K. The thickness of the slabs varies from 0.26 μm to 26 μm. We observe various resonances, whose number and positions depend on the thickness and the angle of the emitted radiation. The experimental results are compared with the theory of Kliewer and Fuchs.     

The far infrared spectrum of 14N16O2

High resolution Fourier transform spectra in the 8–200 cm^-1 spectral region have been used to analyse the pure rotation spectrum of nitrogen dioxide. In this way, the spin rotation levels of the (000) state were accurately measured for K_a up to 14 and N up to 54. Using a hamiltonian which takes the spin-rotation and the hyperfine operators explicitly into account, it has been possible to derive a complete set of molecular parameters (rotational, spin-rotation and hyperfine constants) for the (000) state of ¹⁴N¹⁶O₂ from these experimental data and from the available microwave measurements. Numerous perturbations due to the hyperfine Fermi contact operator were analysed as well as a local resonance [42 0 42, J = 41·5] ? [41 2 40, J = 41·5] due to the electron spin-rotation interaction. Finally, a synthetic spectrum of the (000) ← (000) band of ¹⁴N¹⁶O₂ including all hyperfine transitions has been computed, covering the 0–235 cm^-1 spectral region.     

Observation of “ghosts” produced by gratings in the far ultraviolet

Investigation of four gratings in the far ultraviolet has shown that Lyman ghosts can be very troublesome in this spectral region.     

The 352 nm emission spectrum of difluorodiazirine

Difluorodiazirine fluoresces strongly in the vapor phase showing an extensive band system from about 352 to 451 nm and with no background continuum. The fluorescence is assigned as $\text{A}\text{?}{}^1\text{B}{}_1\text{(nπ}{}^1\text{)-}\text{X}\text{?}{}^1\text{A}{}_1$ and corresponds to the 352 nm absorption system previously studied.The band system is dominated by a progression in ν₁″, the a₁N = N stretching vibration, with ν₄″, the a₁ CF₂ symmetrical deformation vibration, showing a shorter progression.The 0₀⁰ and most others show type B rotational contours but type C bands, involving ν₅″ (a₂), and probably type A bands, involving ν₇″ (b₁) and perhaps ν₆″ (b₁) are also observed.The extremely low intensity of bands involving ν₃″ (a₁) is surprising but there seems to be no reason to doubt the assignment from infrared and Raman data.There is a strong vibrational perturbation affecting some quite strong bands in a region within about 275 cm^?1 of bands 1_n⁰4₀⁰, where n = 0 – 3. The cause of the perturbation is not known.There is no evidence for the emission spectrum consisting of more than one band system.