Electronic emission spectrum attributed to the arsenic monoselenide radical

Six red degraded bands in the region 5300–5700 Å have been observed and attributed to the radical AsSe. Arguments are presented to suggest that the bands arise from two subsystems of a²Π_r(a)-X²Π_r(a) transition and that the value of $\text{Δ}\text{G}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{″}$ is approximately 281 cm^?1.     

The millimeter wavelength spectrum of diatomic sulfur

The gas phase spectrum of diatomic sulfur has been detected in the millimeter wave-length region. Six lines have been measured. The rotational and fine structure parameters obtained are B₀ = 8831.8676 ± 0.006 MHz, D₀ = 5.9 ± 0.7 kHz, λ₀ = 353040 ± 27 MHz, and γ₀ = ? 200.9 ± 0.7 MHz. In addition, reanalysis of EPR data has yielded g_z + 1.18g_n = 2.0021 + 0.0014 and g_z - g_⊥ = ?0.0089 ± 0.0017. On the basis of the frequencies obtained in this work, it was also possible to exclude the assignment of several interstellar emissions to the sulfur dimer.     

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.     

The absorption spectrum of carbonyl selenide: Rydberg transitions

The vacuum ultraviolet spectra of the isotopic species OC⁷⁸Se and OC⁸⁰Se have been measured under both low and high resolution down to 1200 Å. Twelve distinct absorption systems have been vibrationally analyzed, and estimates obtained for excited-state geometries in some cases. Observed transitions have been assigned as members of nsσ, npσ, npπ, and nd Rydberg series, and the quantum defects determined. As n increases, the tendency to ($\text{Ω}$, ω)-type coupling also increases.     

On the electronic spectrum of the diatomic molecular ion

Discrete eigenvalues of the electronic Hamiltonian with dilatation analytic potentials for ionized diatomic molecules are shown to depend smoothly on the distancer of the nuclei forr finite and non vanishing. Furthermore the spectrum is analyzed atr=0 andr=∞ and the eigenvalues turn out to be continuous.     

The microwave spectrum of the FeS radical

The rotational spectrum of the iron monosulfide radical, FeS, was measured in the frequency region of 220-390 GHz with a source-modulated millimeter/submillimeter-wave spectrometer. The radical was efficiently produced in a free space absorption cell by a dc discharge in a mixture of Ar and H₂S with a stainless-steel hollow cathode. Several series of paramagnetic lines were detected with intervals of about 12 GHz. The four series having relatively strong intensity were assigned to FeS in the vibrationally ground state of the X⁵Δ_i electronic state, two series to that in the vibrationally excited state, and five series presumably to FeS in the electronically excited state, . The effective molecular constants were determined for FeS in the X⁵Δ_i electronic state. The components of the vibrationally ground state showed an apparent shift from the typical pattern of the state. In addition, the fine structure of the state was found to be far from a regular pattern expected for a state. A trial analysis including electronic interaction between the and states was carried out, but it was not possible to explain the spectral lines of both electronic states simultaneously. Reasons for the heavily perturbed spectral patterns are discussed.     

The microwave spectrum of the SF radical

The rotational spectrum of the SF radical in the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state was observed by using a source-modulation microwave spectrometer with a 1-m-long discharge cell. The SF radical was generated directly in the cell by a dc discharge in an $\text{OCS}\text{CF}{}_4$ mixture. A previous measurement of the microwave spectrum in the ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ state was also extended to higher-J transitions. The least-squares analysis of all the observed spectral lines gave the B₀ rotational constant and the D₀ centrifugal distortion constant to be 16 576.9140(46) and 0.02924(10) MHz, respectively, where the values in parentheses denote 2.5 times the standard deviations. The Λ-doubling constant p_v was found to be extremely small, 3.409(44) MHz, and it was presumed that contributions of ²Σ⁺ and ²Σ^? states to the Λ doubling cancel each other. All the four fluorine hyperfine coupling constants were also determined, from which the spin density on the F atom was calculated to be 0.13.     

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 microwave spectrum of the SiCl radical

The microwave spectrum of ²⁸Si³⁵Cl, the most abundant isotopic species of the silicon monochloride radical, was observed in both the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ spin states of the ground vibronic state. The SiCl radical was produced in a flow cell by a dc discharge in SiCl₄. The observed transitions were $\text{J =}\text{7}\text{2}\text{←}\text{5}\text{2}\text{up to}\text{21}\text{2}\text{←}\text{19}\text{2}$ for both the spin states, and the observed frequencies were subjected to the least-squares analysis to yield accurate molecular constants as follows: B₀ = 7652.3048(23), D₀ = 0.007017(14), A_J = ?0.8392(16), p₀ + 2q₀ = 138.660(98), q₀ = 0.20(17), $\text{a + (b + c)}\text{2}\text{= 37.50(28)}$, $\text{a ? (b + c)}\text{2}\text{= 49.84(73)}$, b = 9(12), d = 46.40(94), and eQq₁ = ?23.13(96), all in MHz with 3σ in parentheses. The positive sign of the Λ-doubling constant, p₀, indicates that the contributions of ²Σ^? states dominate over those of ²Σ⁺ states. The spin and orbital averages of the unpaired-electron distribution were calculated from the observed hyperfine coupling constants and were discussed in terms of the electronic structure of the molecule.     

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.     

Microwave spectrum and hyperfine structure in the rotational spectrum of diatomic gallium iodide

The J = 3←2 rotational transition of diatomic GaI molecule has been measured in the microwave region. The molecules were produced by a reaction of gallium and lead iodide in the heated zone of a splitted wave guide. The lines were observed in the 10-GHz frequency region at a reaction temperature 270–350°C. Molecular parameters have been derived for ⁶⁹Ga¹²⁷I and ⁷¹Ga¹²⁷I from the analysis of the hyperfine structure. Systematic variations in quadrupole coupling constants in III_a halides have been observed. Vibrational dependence of the nuclear quadrupole interaction for ⁶⁹Ga¹²⁷I can be written as follows: $\text{eq}{}_{\mathrm{<mtext>v</mtext>}}\text{Q(}{}^{69}\text{Ga}\text{) = ?81.29(25) + 0.43(30)(v +}\text{1}\text{2}\text{)}\text{MHz}$, $\text{eq}{}_{\mathrm{<mtext>v</mtext>}}\text{Q(}{}^{127}\text{I}\text{) = ?369.35(10) ? 2.54(16)(v +}\text{1}\text{2}\text{)}\text{MHz}$.     

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 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.     

The millimeter wave spectrum of phosphorus oxychloride

Millimeter wave rotational spectra of phosphorus oxychloride (OPCl₃) in the ground and excited vibrational states have been recorded and analyzed. The v₅ = 1 and v₆ = 1 state spectra show large splittings due to l resonance and the effect of the 2, -1 term r_t. Coriolis constants have been obtained for the two lowest degenerate states. The spectra of the asymmetric top species OP³⁵Cl₂³⁷Cl have been analyzed and centrifugal distortion constants obtained. These have been used to determine the harmonic force field of the molecule.