The 2ν5 overtone bands of perchloryl fluoride

The high-resolution infrared spectra of the monoisotopic species F³⁵Cl¹⁶O₃, F³⁷Cl¹⁶O₃, F³⁵Cl¹⁸O₃ and F³⁷Cl¹⁸O₃ have been studied in the region of the 2ν₅ overtones, from 1100 to 1200 cm⁻¹. Both the parallel and the perpendicular components are clearly observed in the spectra, their origins differing by about 0.4 cm⁻¹. In each spectrum about 2000 transitions have been assigned, 35% of them belonging to . The parallel and perpendicular bands in each manifold have been analyzed separately since no evidence of perturbations has been observed. The rovibration parameters of the v₅ = 2, l₅ = 0 and v₅ = 2, l₅=?2 excited states have been obtained. For the four species combining the and band origins with those of the ν₅ fundamentals the harmonic wavenumbers, , and the x₅₅ and g₅₅ anharmonicity constants have also been derived.     

The 2ν4 overtone bands of FClO3

The high resolution infrared spectrum of the mono-isotopic species F³⁵Cl¹⁶O₃ has been studied in the region of the 2ν₄ overtone, from 2560 to 2680 cm⁻¹. The perpendicular component is strong and clearly observed while the parallel component is very weak and almost completely hidden by the perpendicular one. Their origins differ by 12.6 cm⁻¹, the being located at higher wavenumbers. The band is perturbed by the anharmonic interaction between the v₄ = 2, l₄ = ?2 and v₂ = v₄ = v₅ = 1, l₄ = l₅ = ±1 excited states, both of E symmetry. In total 3157 transitions have been assigned, 83% of these to , 12% to , and 5% to . The three bands have been analyzed simultaneously, taking into account the Fermi resonance effective between the excited states of E symmetry. The ro-vibration parameters of the excited states have been obtained, including the deperturbed band origins of and , at 2628.5890(4) and 2619.3342(5) cm⁻¹, respectively. The W₂₄₅ anharmonic constant is equal to 4.0161(4) cm⁻¹. The x₄₄+g₄₄ and x₂₄+x₄₅+g₄₅ anharmonicity constants have been derived from the obtained band origins and those of ν₄ and ν₂ + ν₅.     

Near infrared emission spectrum of HCN

The emission spectrum of H¹³CN at 1370 K has been recorded with a hot gas high resolution FT-IR emission apparatus [1] in the wavenumber region of with a resolution of . This work reports the analysis of 50 subbands for the H¹³CN isotopologue of hydrogen cyanide in the 2ν₁ wavenumber region. 23 rovibronic states of H¹³CN including the rovibronic states at have been characterized for the first time and for seven other states it was possible to improve the existing spectroscopic constants substantially. The dense emission spectrum was analyzed with the spectrum analysis software SyMath™ implemented in the Mathematica™ computer algebra system [1].     

Absorption spectra of AsH2 radical in 435-510 nm by cavity ringdown spectroscopy

The absorption spectra of jet-cooled AsH₂ radicals were recorded in the wavelength range of 435-510 nm by cavity ringdown spectroscopy. The AsH₂ radicals were produced by pulsed DC discharge in a molecular beam of a mixture of AsH₃, SF₆, and argon. Seven vibronic bands with fine rotational structures have been identified and assigned as the , , and (n = 1-3) bands of the electronic transition. Based on the previous studies of AsH₂ radical, rotational assignments and rotational term values for each band were obtained, and the molecular parameters including vibrational constants, rotational constants, centrifugal distortion constants, and spin-rotation interaction constants were also determined.     

The millimetre-wave rotational spectrum of phenylacetylene

The room-temperature rotational spectrum of phenylacetylene (C₆H₅CCH), was studied at frequencies up to 340 GHz. Extensive new measurements, covering rotational transitions with quantum number values up to J=140 and K_a=59, allowed determination of precise spectroscopic constants for the ground state and for the lowest two excited vibrational states, v₂₄=1 and v₃₆=1. The two excited states belong to the lowest B₁ and B₂ symmetry normal modes and their rotational transitions are very strongly perturbed by a-axis Coriolis resonance. A successful fit of the resonance is reported, resulting in and , in good agreement with results of ab initio computations.     

A general formula of two-dimensional Franck-Condon integral and the photoelectron spectroscopy of sulfur dioxide

We derived a general formula of Franck-Condon integral for two-dimensional harmonic oscillators () taking into account the Duschinsky effect and applied it to study the photoelectron spectroscopy of SO₂ and . The equilibrium geometries and harmonic vibrational frequencies of , SO₂ and were calculated by using the density functional theory (B3LYP functional) and the coupled cluster singles and doubles with perturbative triples [CCSD(T)] methods with various basis sets up to 6-311+G(3df) and aug-cc-pVTZ. The adiabatic ionization energy and electron affinity were computed by using the CCSD(T) method extrapolated to the complete basis set limit with aug-cc-pVXZ (X = D, T, Q, 5). The simulated photoelectron spectra of both SO₂ and are in accord with the experiment. While the Duschinsky effect plays a role for some weak transitions of SO₂, it can be neglected for . A splitting observed in the experimental photoelectron spectrum of SO₂ is interpreted as contributing from hot bands and combination bands of ν₁ and ν₂, rather than arising from perturbation of a potential barrier as previous researchers proposed. The calculated adiabatic ionization energy and electron affinity are in agreement with the experiment within 0.027 and 0.040 eV, respectively.     

Time-resolved infrared diode laser spectroscopy of the ν1 (C-O stretch) band of the CoCO radical

Infrared spectrum of the cobalt carbonyl radical CoCO produced by the 193 nm excimer laser photolysis of cobalt tricarbonyl nitrosyl Co(CO)₃NO was observed by time-resolved diode laser spectroscopy. More than 600 lines were identified as belonging to the ν₁ (C-O stretch) fundamental band, consisting of the Ω=5/2 and 3/2 subbands, and the associated hot bands , , , and . The ²Δ_i electronic ground state of CoCO was experimentally confirmed. The ν₁ band origins are 1974.172582(93) cm⁻¹ and 1973.53178(14) cm⁻¹ for the Ω=5/2 and 3/2 subbands, respectively. The rotational constant in the ground state was determined as B₀=4427.146(50) MHz. The centrifugal distortion constant D₀=1.1243(68) kHz was obtained for the Ω=5/2 substate of the ground state. The equilibrium rotational constant B_e=4435.44(14) MHz was derived, together with the vibration-rotation interaction constants.     

The quark model and b baryons

The recent observation at the Tevatron of (uub and ddb) baryons within 2 MeV of the predicted Σ_b-Λ_b splitting and of baryons at the Tevatron within a few mega electron volts (MeV) of predictions has provided strong confirmation for a theoretical approach based on modeling the color hyperfine interaction. The prediction of  = 5790-5800 MeV is reviewed and similar methods used to predict the masses of the excited states and . The main source of uncertainty is the method used to estimate the mass difference m_b-m_c from known hadrons. We verify that corrections due to the details of the interquark potential and to Ξ_b- mixing are small. For S-wave qqb states we predict , and . For states with one unit of orbital angular momentum between the b quark and the two light quarks we predict , and . Results are compared with those of other recent approaches.     

Rovibrational spectroscopy of the Fermi-interacting ν4 = 1 and ν3 = ν6 = 1 levels of DCF3

The high-resolution infrared spectrum of deuterated fluoroform (DCF₃) was studied in the 700 and 1200 cm⁻¹ regions, with the aim of assigning and analyzing the ν₄ CF₃ asymmetric stretching vibration. The Fermi-type anharmonic coupling between the ν₄ = 1 and ν₃ = ν₆ = 1 rovibrational levels, already mentioned in an early work of Ruoff et al. [Spectrochimica Acta Part A 31A (1975) 1099-1100], was studied here for the first time under high resolution. Assignments in the ν₃ + ν₆/ν₄ band system were confirmed and extended by the identification of the ν₃ + ν₆ − ν₆ and ν₄-ν₆ bands in the 700 cm⁻¹ region, the latter being enhanced near the Fermi crossings of the studied levels. Data from both the hot and difference bands were included in the analysis. The close separation of the studied vibrational levels of about 14.8 cm⁻¹ produces a large variety of resonance crossings which involve levels with . Besides the Fermi () and Coriolis () resonances, they were accounted for by inclusion of additional higher-order ( and ) interaction terms between the vibrational states. The least-squares fit of more that 16,000 vibration-rotation transitions provides a quantitative reproduction of data in all bands.     

Quantum critical behaviour in doped Y bB12 studied by ab initio calculations

The Kondo insulator Y bB₁₂ is known to undergo a transition to the metallic state with doping or under an external magnetic field. Within the virtual crystal approximation (VCA), we calculated the occupation of the Yb 4f and 5d shells, and , as a function of doping of Y bB₁₂ with the rare earths Tm and Lu. We found that exhibits an anomalous change at the critical concentration of the dopant, in agreement with experiment ( for Y b_1−xLu_xB₁₂ and for Y b_1−xTm_xB₁₂). We suggest that the critical behaviour seems to be strictly connected with the change of and in consequence the change of the Yb valency.     

The effect of the Bi source on optical properties of Bi2Te3 nanostructures

nanostructures were synthesized by using different Bi sources via a simple solvothermal process, in which and BiCl₃ were used as the Bi sources. Optical properties of nanostructures prepared with and BiCl₃ as the Bi sources were investigated by micro-Raman spectroscopy. The Raman scattering spectrum of hexagonal nanoplates prepared by using as the Bi source shows that the infrared (IR) active mode A_1u, which must be odd parity and is Raman forbidden for bulk crystal due to its inversion symmetry, is greatly activated and shows up clearly in the Raman scattering spectrum. We attribute the appearance of the infrared active A_1u mode in the Raman spectrum to crystal symmetry breaking of hexagonal nanoplates. However, the Raman scattering spectrum of nanostructures with irregular shape prepared by using as the Bi source only exhibits the two characteristic Raman modes of crystals. Micro-Raman measurements on nanostructures with different morphologies offer us a potential way to tailor optical properties of nanostructures by controlling the morphologies of the nanostructures, which is very important for practical applications of nanostructures in thermoelectric devices.     

Highly excited rovibrational states of HNC

The emission spectrum of HCN has been recorded at 1463 K using hot gas molecular emission (HOTGAME) spectroscopy in the wavenumber region of 2900–3500 cm⁻¹ with a resolution of 0.01 cm⁻¹. The dense emission spectrum was analyzed with the spectrum analysis software SyMath™ implemented in the Mathematica™ computer algebra system. This work reports the analysis of the band series up to v₂ = 8 and of the band series up to v₂ = 6.36 rovibronic (v₁, v₂, l, e/f, v₃) substates of HCN including all l = 0, 2, 4, 6, 8 sublevels of the highly excited bending combination mode have been characterized for the first time and for the 22 known vibrational sublevels it was possible to improve the existing spectroscopic constants substantially. 18 (v₁, v₂, l, v₃) vibrational sublevels are located for the first time relative to the 00⁰0 state. The analysis reported here includes rovibrational states up to very large rotational excitations of J = 60–80. For the combination states the rotational states have been determined up to J = 86 which corresponds to 7000 cm⁻¹ rotational excitation energy, this state is only 2000 cm⁻¹ below the isomerization barrier. It was possible to determine for the first time the L_v high order rotational constant for many states reported in this work.     

Synthesis, optical properties and crystal structures of carbazole end-capped phenylene ethynylene blue light-emitting materials

A class of highly fluorescent and stable carbazole end-capped phenylene ethynylene compounds have been synthesized and characterized. They show high extinction coefficients of absorption () and quantum yields of fluorescence (; Φ_F=0.52-0.73) in dichloromethane. The solid state absorptions and emissions are significantly red-shifted from the dilute solution ones (; ). Their photoluminescent properties and crystal structures have been investigated with the aim of providing a basis for elucidating the structure-physical property relationships. These data indicate their potential use as blue-emitting materials in organic light-emitting diodes (OLEDs).     

Laser excitation spectrum of C3 in the region 26 000-30 700 cm

The vibrational structure of the electronic state of C₃ in the region 26 000-30 775 cm⁻¹ has been re-examined, using laser excitation spectra of jet-cooled molecules. Rotational constants and vibrational energies have been determined for over 60 previously-unreported vibronic levels; a number of other levels have been re-assigned. The vibrational structure is complicated by interactions between levels of the upper and lower Born-Oppenheimer components of the state, and by the effects of the double minimum potential in the Q₃ coordinate, recognized by Izuha and Yamanouchi [16]. The present work shows that there is also strong anharmonic resonance between the overtones of the ν₁ and ν₃ vibrations. For instance, the levels 2 1⁺ 1 and 0 1 ⁺ 3 are nearly degenerate in zero order, but as a result of the resonance they give rise to two levels 139 cm⁻¹ apart, centered about the expected position of the 2 1⁺ 1 level. With these irregularities recognized, every observed vibrational level up to 30 000 cm⁻¹ (a vibrational energy of over 5000 cm⁻¹) can now be assigned. A vibronic level at 30181.4 cm⁻¹, which has a much lower B′ rotational constant than nearby levels of the state, possibly represents the onset of vibronic perturbations by the electronic state; this state is so far unknown, but is predicted by the ab initio calculations of Ahmed et al. [36].     

Inelastic neutrino scattering off stable even-even Mo isotopes at low and intermediate energies

Inelastic neutrino scattering cross sections for the even-even Mo isotopes (contents of the MOON detector at Japan), at low and intermediate electron neutrino energies (?_i≤100 MeV), are calculated. MOON is a next-generation double beta and neutrino-less double-beta-decay experiment which is also a promising facility for low-energy neutrino detection. The nuclear wave functions required in this work have been constructed in the context of the quasi-particle random phase approximation (QRPA) and the results presented refer to , , , and isotopes.     

Deep-UV high resolution cavity ring-down spectroscopy of the Schumann-Runge bands in O2 and O2 at wavelengths 197-203 nm

With the use of a novel titanium:sapphire laser source delivering, upon fourth harmonic generation, narrowband and tunable radiation in the deep-UV, spectroscopic studies were performed on weak Schumann-Runge bands of oxygen. Improved values for rotational and fine structure molecular parameters for the , v = 0-2 states of ¹⁶O₂ were determined, as well as values for the v = 0-1 states in ¹⁸O₂. Signal detection was accomplished via cavity ring-down spectroscopy.     

The 313 nm band system of SeO2. Part 2: rotational structure

Rotational analyses of the first four bands in the ν₁ progression of the transition of SeO₂ at 312.7 nm are reported. The gas phase sample, which contained selenium isotopes in natural abundance, was formed in a free jet expansion from a heated nozzle source. The rotational constants for the state show a rather erratic dependence on v₁^′, consistent with the identification of small, local perturbations in the rotational structure. The A-rotational constant shows a particularly irregular dependence on v₁^′. The r₀ structure was therefore determined from the B and C values of ⁸⁰SeO₂ to be:

     

Diode laser overtone spectroscopy of CO2 at 780 nm

Overtone absorption lines of ¹²C¹⁶O₂ have been examined by using a tunable diode laser (TDL) spectrometer in the region around . The spectrometer sources are commercially available double heterostructure InGaAlAs TDLs operating in the “free-running” mode, which allowed the detection of the line positions within . The observed carbon dioxide absorption lines belong to the ν₁+5ν₃ ro-vibrational band with rotational quantum number J up to 48. The minimum absorbance detected by the spectrometer (?5×10^-6) permitted to observe the weakest lines having the absorption cross section of the order of .     

FTIR and diode laser spectroscopy of isobutylene: Analysis of the rotational structure in the v28 fundamental band

Rotational structure in the fundamental band of isobutylene has been examined at room temperature using a combination of FTIR and Pb-salt diode laser instruments. The highest spectral resolution for the FTIR measurements was 0.125 cm⁻¹. Even at this resolution however, rotational structure for the band could be observed and appeared to possess a very regular pattern. A preliminary spectral assignment was obtained using the Watson/Gora asymptotic approximation for a rigid oblate asymmetric rotor. Within this approximation, the band origin was determined to be 890.937 (4) cm⁻¹. Excited state rotational constants, without the inclusion of centrifugal distortions terms, are A = 0.3033(16), B = 0.2801(12) and C = 0.15362 (8) cm⁻¹ respectively. Finally, a full set of spectroscopic constants, including quartic centrifugal distortion constants, were obtained for the band by including the high resolution Pb-salt spectra.     

The overtone spectrum of C2D2 and C2H2 by ICLAS-VECSEL near 1 μm

The intracavity laser absorption spectra (ICLAS) of dideuteroacetylene, C₂D₂, and acetylene, C₂H₂, have been recorded between 1.03 and 0.99 μm with a vertical external cavity surface emitting laser (VECSEL) leading to the observation of seven and six bands, for C₂D₂ and C₂H₂ respectively, most of them newly reported. The strong ν₁+3ν₃ band of C₂D₂ at is found accompanied by the two Π-Π hot bands with v₄=1 and v₅=1 lower state and by the ν₂+3ν₃+2ν₄ band near . This last band results from an intensity transfer from the ν₁+3ν₃ band induced by the 1/244 anharmonic interaction. The ν₁+3ν₃ band of , present in natural abundance in the sample, could also be detected at in full agreement with local mode model predictions. The different bands of both C₂H₂ and C₂D₂ were found mostly unperturbed and the spectroscopic parameters retrieved from the rovibrational analyses agree satisfactorily with the predictions of the respective effective Hamiltonian models.