E. N. Moskvitina

Molecular constants of the NbN molecule

Abstract Absorption spectrum of NbN has been obtained in the 560–670 nm region by intracavity laser spectroscopy. Vibrational and rotational analyses of 3φ - 3Δ transition has been caried out. Molecular constants for the upper (3φ) and ground (3Δ) states have been determined.

INTRACAVITY ELECTRONIC ABSORPTION SPECTRA OF MOO AND WO MOLECULES IN THE VISIBLE REGION

Abstract Absorption electronic spectra of MoO and WO molecules have been investigated by a intracavity laser technique in the region 550–800 run. New features have been discovered. As for MoO molecule the rotational analysis of the four bands have been carried out for the first time. Two of these bands were referred to 0–0 transitions arisen from the new (probable triplet) low-lying electronic state, two other bands were referred to transitions arisen from excited components of X5II ground state. As for WO molecule the rotational analysis of 0–0 and 1–0 bands represented A-X and B-X systems have been carried out for the first time. The new band has been discovered which has been referred to new electronic transition. Molecular constants of new states of both molecules studied have been evaluated.

Intracavity laser spectroscopy of the HfCl molecule. Analysis of rotational structure of new bands of the 2Δ-X2Δ electronic transition

Electron absorption spectrum of the HfCl molecule was studied in the 550–800 nm region using intracavity laser spectroscopy. HfCl molecules were obtained using the passage of an impulse electric discharge through a mixture of HfCl4 and He vapors. A cuvette with the mixture of gases was placed in a dyelaser resonator cavity. The spectra were registered using diffraction spectrograph (resolution capability 240000). The high sensitivity of the intracavity method made it possible to detect in the HfCl spectrum new bands with a resolved rotational structure. Rotational analyses of the given bands were performed and the molecular constants were determined.

Spectroscopy of Hafnium Monohalides

Abstract The modern intracavity laser method has been applied to study electronic spectra of the hafnium monohalides molecules. Results of new investigation of HfF and HfBr molecules are presented: the bands at 589.3, 590.6, and 593.1 nm observed in intracavity laser spectra of HfF4 have been assigned to the bands of HfF or ionized HfF; new molecular constants of the HfBr molecule have been obtained. Spectroscopic studies of HfCl and Hfl molecules are discussed, and the most reliable molecular constants of HfCl, HfBr, and Hfl molecules are recommended.

The Electronic Absorption Spectrum of Zirconium Monooxide

Abstract The absorption spectrum of ZrO has been obtaioed io the 560-670 nm region by intracavity laser spectroscopy. Vibrational analyses of e3Π -a3Δ and d3Φ -a3Δ transitions have been carried out with accounting for an anomalous multiplet splitting. Molecular constants for the upper e3Π and d3Φ states have been determined.

Intracavity laser spectroscopy of the HfCl molecule. A new electronic transition 2Π3/2-X2Δ3/2

The electronic absorption spectrum of hafnium monochloride (HfCl) has been investigated in the visible region in order to find the bands of HfCl related to the electronic states that were obtained from ab initio calculations. Two new bands that resulted from the transition from the X2Δ3/2 ground state to a 2Π3/2 electronic state predicted by calculations were detected in the spectrum of HfCl using the intracavity laser technique. A rotational analysis of these bands was carried out and previously unknown rotational constants for the 2Π3/2 state were determined: B0 = 0.104977(34) cm−1 and ae = 0.00052(1) cm−1.

Electronic spectra and molecular constants of zirconium mononitride

The electronic spectra and structure of zirconium mononitride were considered. The electronic vibrational-rotational spectrum of ZrN was obtained by intracavity laser spectroscopy within the 550–750 nm region. The spectrum was analyzed and the molecular constants of the ground X2Σ and excited A2Π electronic states were calculated. On the basis of the obtained experimental data and critical analysis of all the information on ZrN spectrum studies, the most reliable set of molecular constant values was recommended.

Double-pulse laser ablation applied to reactive PLD method for synthesis of carbon nitride film: A second laser shot delay

Carbon nitride films were deposited using ablation of graphite target by second harmonic radiation of Nd:YAG laser in nitrogen atmosphere. To produce high hardness films, the deposited particles should have sufficient kinetic energy to provide their efficient diffusion on a substrate surface for formation of crystal structure. However, a shock wave is arisen in ambient gas as a consequence of laser plasma explosive formation. This shock wave reflected from the substrate interacts with plume particles produced by the first laser pulse and decreases their kinetic energy. This results in decrease of film crystallinity. To improve film quality, two successive laser pulses was proposed to be used. At adjusting time delay, the particles induced by the second pulse wilt serve as a piston, which will push forward both stopped particles ablated by the first pulse and arisen from chemical reactions in ambient gas. An X-ray photoelectron spectroscopy (XPS) analysis of deposited films has shown an increase of content of sp3 carbon atoms corresponding to crystalline phase, if double-pulse configuration is employed. The luminescence of excited C2 and CN molecules in laser plume at different distances from the target was studied to optimize the delay between laser pulses.

Experimental and theoretical investigation of the electronic structure and spectra of the MoN molecule

The electronic absorption spectra of the MoN molecule have been measured by intracavity laser spectroscopy, and its electronic structure has been calculated by the X..cap alpha..-SW method. The absorption spectra showed 69 quanta (of which 55 were obtained for the first time), which were assigned on the basis of their isotope shifts to the MoN molecule. The energies and oscillator strengths of the one-electron transitions to states lying below approx. 4 eV from the ground and the lowest excited electronic states were calculated in the transition-state approximation. The results are presented.