Fourier transform emission spectroscopy of the TiF radical in the 407 nm region

Ultraviolet emission spectra of the TiF radical in the 407 nm region have been observed at a resolution of 0.04 cm⁻¹ using a Fourier transform spectrometer. A new electronic assignment of ⁴Γ–X⁴Φ has been proposed. Rotational analysis has been obtained for the 0–0 and 1–1 vibrational bands of the ⁴Γ_5/2–X⁴Φ_3/2, ⁴Γ_9/2–X⁴Φ_7/2, and ⁴Γ_11/2–X⁴Φ_9/2 subbands and the 0–0 band of ⁴Γ_7/2–X⁴Φ_5/2. The lower state rotational and centrifugal distortion constants are consistent with the previous results [J. Mol. Spectrosc. 184 (1997) 186; J. Chem. Phys. 119 (2003) 9496], to the conformation that the lower state of the 407 nm band is the ⁴Φ ground electronic state. Rough estimates of the vibrational interval ΔG(1/2) and the spin–orbit coupling constant A in the ⁴Γ state were also obtained.     

H2S : First Observation of the (70,0) Local Mode Pair and Updated Global Effective Vibrational Hamiltonian

The absorption spectrum of H₂S has been recorded by intracavity laser absorption spectroscopy in the spectral region 16 180–16 440 cm⁻¹ corresponding to an excitation of the (70^±, 0) local mode pair. Seventy-seven sublevels could be rotationally assigned and fitted with a rms of 0.009 cm⁻¹ by considering the (70^±, 0) local mode pair as isolated. The corresponding vibrational terms combined with all the levels reported in the literature were used to refine the effective vibrational Hamiltonian parameters of H₂³²S. The importance of the Fermi-type interaction is discussed.     

The LIF Excitation Spectrum of Jet-Cooled 2,6-Dicyano-3, 5-Dimethylaniline

The laser-induced fluorescence (LIF) excitation spectrum of jet-cooled 2, 6-dicyano-3,5-dimethylaniline (DCDMA) has been measured in the spectral range of 29,750–32,250cm^–1. The band origin at 29,860.8 cm^–1 and as many as 250 vibrational bands have been identified in the excitation spectrum. The analysis of the excitation spectrum of DCDMA gives more than 28 vibrational modes involving aromatic ring oscillations and oscillations related to the substituent groups. DCDMA is nonplanar in the ground state, with the NH₂ plane at about 9° with respect to the molecular plane (RHF/6-31G*). The singlet excited molecule is planar (CIS/6-31G*). Both CIS/6-31G* and CASPT2 calculations predict that the lowest excited state of DCDMA involves a dominant HOMO-LUMO excited configuration. The characteristic feature of the excitation spectrum of DCDMA is the presence of progressions in the low-frequency mode, 112 cm^–1. The calculations suggest that this mode and some other active modes involve motions of the amino group and strongly interacting adjacent cyano substituents.     

Calculation of the Spectroscopic Constants and Strength of the Electron Transition <Emphasis Type="Italic">A</Emphasis>0<Superscript>+</Superscript>-<Emphasis Type="Italic">X</Emphasis><Superscript>1</Superscript>Σ<Superscript>+</Superscript> of the AgAu Molecule

The vibrational, rotational, and centrifugal constants for the electronic states A and X ¹Σ⁺ of the AgAu molecule have been calculated. The calculation is based on the Morse potential functions that were used to approximate the real potential curves of the ground and excited states of AgAu. Using the experimental data on the lifetime of the vibrational levels of the excited electronic state, the strength of the A-X transition was calculated.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 176–180, March–April, 2005     

The IR absorption spectrum of 2 - aminothiazolid - 4 - one

A mechanical model has been used to calculate the frequencies in the vibrational spectrum of the imine and amine tautomeric structures for this compound; the IR spectrum for the crystalline state has been deduced for the range 80–3500 cm^–1, and a discussion is given for the effect of the tautomeric prototropic forms on the vibrational spectrum.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 9, pp. 76–82, September, 1971.     

Torsion-rotation far-infrared spectrum of O-18 methanol

High-resolution Fourier transform spectra have been recorded from 15–470 cm^–1 for the far-infrared trosion-rotation band of O-18 methanol in the vibrational ground state. So far, 57 subbands have been assigned in the 15–220 cm^–1 region for a wide range of rotational and torsional states, and their J-independent origins have been determined to an estimated accuracy of ±0.01 cm^–1. The observed origins were found to deviate in many cases by several tenths of a cm^–1 from the values calculated with the previous molecular parameters. Together with 4 known microwave origins, the new data have been fitted to a model torsion-rotation Hamiltonian in order to refine the set ofb-type molecular constants for the ground state. With the new parameter set, the experimental subband origins are reproduced with an rms error of ±0.02 cm^–1, representing a substantial improvement over the earlier situation. The spectroscopic results have also been of great assistance with our assignments of optically-pumped FIR laser emission in CH₃ ¹⁸OH, in providing FIR data for checking the identification of the IR-pump/FIR-laser transition systems through combination loop relations.     

Influence of Vibrational Excitation of Triplet Molecules of Anthraquinone on the Photochemical Processes in Gas Mixtures with Amines

By the quenching of the delayed fluorescence (DF) of anthraquinone vapors by aliphatic amines (diethylamine, dibutylamine, cyclohexylamine) and pyridine the photoinduced processes proceeding with the participation of vibrationally excited triplet molecules of anthraquinone have been investigated. The DF quenchingrate constants K _q varying from 1·10⁶ sec^–1·torr^–1 in mixtures with diethylamine to 7·10³ sec^–1·torr^–1 in mixtures with pyridine have been estimated. A correlation between the values of K _q and the ionization potentials of foreign gases confirming the important role of interactions with charge transfer in the quenching of triplet molecules in the gas phase has been established. The influence of other relaxation processes on the DF quenching is considered. It is shown that the intermolecular vibrational relaxation in the T ₁ triplet state leading to the establishment of relaxation equilibrium at a vibrational temperature T _vib considerably increasing the medium temperature is the fastest process among the biomolecular processes (rate constants K _col ^V > 10⁶ sec^–1·torr^–1 > K _q). The values of T _vib and the vibrational energies E _vib of the triplet molecules after the energy exchange in the collisional complex have been estimated. It has been concluded that the photochemical reaction yield is determined by the intermolecular processes proceeding in the T ₁ state at a vibrational equilibrium characterized by high values of T _vib. The influence of E _vib of triplet molecules on the DF quenching rates at a photoinduced electron transfer is considered.     

Effect of hydroxyl and oxygen ions on optical stability of F-centers in KBr crystals

The effect of the anionic impurities OH^–, O ₂ ^§- , and O^2– on the optical stability of F-centers in KBr crystals was investigated. It is shown that the stability of F-centers is independent of the presence of hydroxyl ions (OH^–) and molecular oxygen ions (O ₂ ^– ) in the crystal lattice. It is suggested that the low stability of F-centers in KBr-KOH crystals is due to doubly charged oxygen ions.Translated from Izvestiya Vysshikh Uchebnykh Zavendenii, Fizika, No. 10, pp. 107–112, October, 1972.     

Microwave and low-frequency vibrational spectra of bullvalene

The microwave spectrum of bullvalene has been investigated in the region 18–40 GHz. In addition to transitions in the ground vibrational state, transitions arising from five excited vibrational states below 600 cm⁻¹ have also been observed. A combination of microwave intensity measurements and infrared and Raman data has been utilized to assign these vibrations. Three of the vibrations are E-type modes at 241, 355, and 588 cm⁻¹. One is an A₁-type mode at 445 cm⁻¹, and another is an A₂-type at 266 cm⁻¹. The microwave spectrum indicates the presence of a first-order Coriolis interaction for the E modes at 241 and 588 cm⁻¹. The first-order Coriolis coupling constant q = 0.557 MHz for the 241 cm⁻¹ vibration. The spectral results are consistent with C_3v symmetry for bullvalene.     

Lifetimes of formaldehyde (A2) in the diffuse region

Lifetimes for the first excited singlet state of H₂CO, D₂CO, and HDCO have been measured from linewidths. In the region of 7000–9000 cm⁻¹ of vibrational energy, lifetimes between 2 and 14 psec were observed. These lifetimes increase with decreasing energy and may be smoothly extrapolated to the results below 4000 cm⁻¹. The H₂CO lifetimes are shorter than D₂CO lifetimes but longer than those for HDCO.     

Methanol laser lines from torsionally excited co stretch states, and from OH-bend, CH3-rock, and CH3-deformation states

Using a quasi-CW CO₂ oscillator-amplifier combination with peak power 300 Watt, we have generated FIR laser emission in weak absorption bands of CH₃OH. 40 new lines are reported, and their wavelengths are measured with a relative accuracy of 5×10^–5. A total of 72 lines are assigned. 34 of these involve torsional n=1, 2, and 3 states of the CO stretch and the vibrational ground state. The remaining lines are associated with the CH₃-rock, OH-bend, and CH₃-deformation modes. The latter are located 1460 cm^–1 above the ground state, and are pumped by simultaneous vibrational excitation and torsional deexcitation.     

Tunneling current-voltage characteristics of Ti-silicide/p− Si/p+ Si Schottky diodes

The tunneling current-voltage characteristics of Ti-silicide/p^– Si/p⁺ Si Schottky diodes are analyzed to study the Ti/Si interface properties. By using an MBE-grown 7 nm p^– Si spacer layer, well-defined tunneling structures are obtained. The sharply peaked density of states in a Ga-impurity band is used as a tunneling probe. A state density gap 100 meV around the Fermi energy is observed for a rapidly (20s) annealed (T=550°C) reacted sample. The gap is interpreted by a Ti-rich interfacial silicide film of about 1 nm.     

An ab initio calculation of the vibrational energies and transition moments of HSOH

We report new ab initio potential energy and dipole moment surfaces for the electronic ground state of HSOH, calculated by the CCSD(T) method (coupled cluster theory with single and double substitutions and a perturbative treatment of connected triple excitations) with augmented correlation-consistent basis sets up to quadruple-zeta quality, aug-cc-pV(Q+d)Z. The energy range covered extends up to 20 000 cm⁻¹ above equilibrium. Parameterized analytical functions have been fitted through the ab initio points. Based on the analytical potential energy and dipole moment surfaces obtained, vibrational term values and transition moments have been calculated by means of the variational program TROVE. The theoretical term values for the fundamental levels ν_SH (SH-stretch) and ν_OH (OH-stretch), the intensity ratio of the corresponding fundamental bands, and the torsional splitting in the vibrational ground state are in good agreement with experiment. This is evidence for the high quality of the potential energy surface. The theoretical results underline the importance of vibrational averaging, and they allow us to explain extensive perturbations recently found experimentally in the SH-stretch fundamental band of HSOH.     

The optical absorption of hydroxyl ions associated with divalent calcium in NaCl

The measurements confirmed the association of Ca²⁺ and OH^– in NaCl: CaCl₂ + NaOH, which causes an increase and a shift +0·031 of the OH^– absorption at 2·8, the extinction of the OH^– UV-absorption at 184 nm and the occurrence of new absorption bands between 160 and 210 nm.The measurements were performed at the II. Physikalisches Institut of the University of Stuttgart.     

Submillimeter-wave spectroscopy of HCN in excited vibrational states

Measurements of the rotational spectrum of HCN in excited vibrational states have been extended to higher-J values. The transitions reach J=8←7 around 710 GHz for most vibrational states studied in this investigation and J=22←21 near 2 THz for the (020) and (030) vibrational states. Using a pure sample of gaseous HCN at 350 K, selected states up to one quantum in the C–H stretching vibration at 3311.5 cm⁻¹ have been investigated. Even transitions having two quanta in the C–H stretch could be studied employing a glow discharge in a gas mixture of CH₄ and N₂. Molecular constants in 13 vibrational states have been obtained, several of which have been studied for the first time by rotational spectroscopy. The vibrational temperature in the discharge system is found to be about 1500 K for the stretching vibrational modes and about 600 K for the bending states.     

Radical-Recombination Luminescence of the Uranyl Nitrate Complex in the Adsorbed State

We have investigated the luminescence of uranyl nitrate molecules on the surface of powdery SiO₂ upon excitation by UV light (PhL) and hydrogen atoms (radical-recombination luminescence (RRL)). It has been found that the PhL and RRL spectra have a clearly defined vibrational structure. The luminescence peaks of the adsorbed UO₂ ^2– ion are characterized by a systematic longwave shift from the same peaks of crystalline uranyl nitrate (by 230–430 cm^–1 at 130 K). Moreover, in the adsorption centers the vibration frequencies of UO₂ ^2– are 20–80 cm smaller than in crystalline salt and the RRL bands are 150–350 cm^–1 (130 K) wider than the corresponding PhL bands.     

Viscous How and MOS properties of CaF2-B2O3-GeO2-SiO2 glasses with ionic bonds

The capacitance and voltage (C-V) characteristics of Metal-Oxide-silicon (MOS) capacitors passivated by CaF₂B₂O₃-GeO₂-SiO₂ glasses with OH^– ions, water and fluoride contents were investigated. As the OH^– absorption coefficients of the glass increased, adverse effects on the recovery of hysteresis C-V curve shifts was observed. The content of OH^– ions is closely related to the fluoride content in the CaF2 B₂O₃-GeO₂-SiO₂ glass. The viscous-flow point of the glass was lowered with increasing degree of ionic character obtained from Hannay's equation.     

Microhardness of crystals of KBr-KI solid solutions with Sr2+ and OH− impurities

The microhardness, conductivity, and dielectric-loss angle have been studied in KBr and KI single crystals and in their solid solutions with Sr²⁺ and OH^– impurities. It is shown that the Sr²⁺ impurity dissolves only slightly in KI crystals and in KBr-KI solid solutions having a large KI content. Addition of the anionic OH^– impurity to the molten salts reduces the micro-hardness of KBr but it does not affect that of KI crystals or KBr-KI solid solutions having a large KI content. The composition dependence of the microhardness for KBr-KI solid solutions is constructed on the basis of the microhardness values for the corresponding crystals purified of cationic impurities of different valence.Translated from Izvestiya VUZ. Fizika, No. 10, pp. 18–21, October, 1969.     

The substitution of Fe2+ ions by Ni2+ ions in green rust one compounds

The oxidation of Fe(OH)₂ in the presence of Cl^– or CO ₃ ^2– ions leads, in the first stage of the reaction, to chloride-containing green rust one (GR1), 3Fe(OH)₂· Fe(OH)₂Cl·nH₂O, or carbonate-containing GR1, 4Fe(OH)₂·Fe₂(OH)₄CO₃·nH₂O, respectively. These GR1 compounds give the ferric oxyhydroxides by further oxidation. If a hydroxide Ni _x Fe_1–x (OH)₂ is initially precipitated, the reaction leads to a nickelous-ferric compound isomorphous to the ferrous-ferric GR1, but stable with respect to the oxidizing action of air. Similarly, the oxidation of a nickelous-ferrous hydroxide, in the presence of excess OH^– ions, leads to a nickelous-ferric GR1, a layered hydroxide with anionic interlayers made of OH^– ions and water molecules. The Mössbauer spectra of these nickelousferric GR1 display two ferric doublets, D₀ withIS=0.34 mm/s andQS=0.45 mm/s and D₁ withIS=0.36 mm/s andQS=0.86 mm/s. The existence of a ferrous-ferric GR1 incorporating OH^– ions, a compound never observed so far, is strongly suspected.