Study of the Absorption Characteristics of Transitions in the HOT 2υ2–υ2 Band of the 34SO2 Molecule

Russian Physics Journal - The absorption coefficient of the rovibrational 2υ2–υ2 band of the 34SO2 molecule localized in the region 350–850 cm–1 is studied for the first...     

Vibrational–Rotational Analysis of the Hot 2ν2–ν2 Band of the 15NH2D and 15NHD2 Molecules

Optics and Spectroscopy - High-resolution spectra of the $$2{{\nu }_{2}}{-} {{\nu }_{2}}$$ hot band of the 15NH2D and 15NHD2 molecules are investigated for the first time. The analysis is carried...     

Density functional study of the polymorphism of Cs2C2 and Rb2C2

By density functional theory-based calculations it is shown that in the athermal limit the orthorhombic polymorph of Cs₂C₂ is more stable by ≈7 kJ/mol with respect to the hexagonal modification, while the energy difference between the corresponding two Rb₂C₂-polymorphs is about 4 kJ/mol. The calculations do not corroborate the experimental finding of unusually long and short C-C bond lengths in Cs₂C₂ at low temperatures. This theoretical result is supported by calculations on monomeric LiCCH, where DFT calculations give all bond lengths within 1%.     

Study of the modulated structure of Bi2Sr2CaFe2Ox

The ceramics and single crystals of the Bi₂Sr₂CaFe₂O_x compound were synthesized. The X-ray diffraction data showed orthorhombic symmetry. The lattice parameters are equal toa=5.464 Å,b=5.453 Å,c=31.313 Å. The crystal structure is described by the primitive Bravais lattice with the possible space groups Pbmm. Pbm2 and Pb2₁m. The obtained X-ray patterns show the presence the incommensurate structural modulation with the following parameters: the modulation vector lies in the (100)-plane, the value of the wave-vector componentq _b=0.22(3). The comparison of the obtained results with data for Fe-doped Bi₂Sr₂CaCu₂O_x and Bi₂Sr₃Fe₂O_x are presented. No magnetic peculiarities of the compound were found. Mssbauer measurements of the ceramic samples indicate the presence mainly of Fe³⁺ oxidation state and Fe⁴⁺ (about 20%). The decrease of the quadrupole-splitting values for 2212Fe in comparison with Fe-doped 2212Cu was revealed that may be connected with higher symmetry of the local environment of Fe atoms in 2212Fe.     

Structure of the energy bands in semiconductors of the AIBIIIC2 VI type AgInS2, AgInSe2, AgInTe2

The energy-band structure of the compounds AgInS₂, AgInSe₂, AgInTe₂ is calculated. These compounds are found to have a simple type of conduction band, which consists of several competing maxima lying at different points of the Brillouin zone.     

Low-temperature electron microscopy of the surface of the superconductor Bi2Sr2CaCu2O8

Electron microscopy studies of the microstructure and composition of the surface of the high-temperature superconductor Bi₂Sr₂CaCu₂O₈ are performed. The secondary-electron emission intensity and its temperature dependence are estimated in local regions at temperatures lower than 300 K. The results are interpreted within the secondary-electron emission model.     

Study of the Rotational Structure of the Forbidden ν8 Band of the C2H2D2-CIS Molecule

Russian Physics Journal - The spectrum of the cis-ethylene-d2 (C2H2D2-cis) molecule is recorded with a Bruker IFS 120 HR Fourier spectrometer in the region of 600–1200 cm–1 with...     

Theoretical study of the HeN2+ 2 dication

The structure and stability of the helio nitrogen molecular dication, HeN²⁺ ₂, is investigated by means of standard quantum chemical methods based on both single-reference and multi-reference formalisms. Sequences of correlation consistent basis sets are employed to establish convergence with respect to the size and the quality of the single-particle basis set. MRCI and CASPT2 calculations are reported for the HeN²⁺ ₂ ground-state ion which is found to be metastable. The barrier for the transition state of the reaction HeN²⁺ ₂→ N⁺ …NHe⁺ → N⁺ + NHe⁺ is calculated to be 59.5 kcals mol^?1. The structure of the transition state NHeN²⁺ was also determined from calculations using the MRCI and CASPT2 methods.     

On the low-temperature properties of TmCo2Ge2

In this paper low-temperature magnetic properties of TmCo₂Ge₂ are reported. The compound was investigated by means of magnetic, electrical transport, heat capacity and neutron diffraction measurements. Clear anomalies were found in all of the bulk characteristics at the onset of antiferomagnetically ordered state below 2.4 K. According to neutron diffraction data, Tm magnetic moments are aligned along the c-axis, forming the AFI-type magnetic structure. In the paramagnetic state, the specific heat reveals a distinct Schottky contribution with the total crystal field splitting of about 150 K.     

Zeeman effects in the visible 2B2 ← 2A1 system of NO2

The Zeeman effect facilitates certain rotational assignments in bands of the ${}^2\text{B}{}_2\text{-}{}^2\text{A}{}_1$ electronic system of NO₂. A partial analysis of two bands of this system is reported.     

Study of the superionic system AgI-PbI2-Ag2O-B2O3

The superionic system AgI-PbI₂-Ag₂O-B₂O₃ with two compositions has been prepared. The pelletised samples were investigated with regard to conductivity, modulus and dielectric analysis at various temperatures and frequencies. The activation energy determined for the samples was found to be varying between 0.09 to 0.10 eV. The effect of polarization at the electrode has been analyzed from conductivity spectra. From the impedance and modulus analysis it has been found that the system is non-ideal and there exists a distribution of relaxation times which is independent of temperature.     

High resolution measurements of the line positions and strengths of the 2ν2 band of H2CO

Spectra of the 2ν₂ band of formaldehyde have been obtained with high resolution (0.035 cm^?1). Measurements were made with path lengths of 8, 16, and 24 m and at sample pressures from 0.1 to 0.3 mm Hg at room temperature (～296°K). From these data, the following constants were determined for the 2ν₂ band in wavenumber units: v₀=3471.718±0.004,A=9.3958±030013,B=1.28100±0.00024,C=1.11662±0.00024, Tbbb=-12.8±0.5×10^-6,Taabb=60±5×10^-6. The line strengths were also obtained from the data. The strengths were analyzed to determine the band strength and the rotational factors. At 296°K, the strength of the 2ν₂ band was found to be 15.5 ± 0.9 cm^?1/(cm·atm).     

Toward the 2s-2p spectroscopy of the µp atom

Very recent results relevant to the planning of laser spectroscopy of the 2s-2p splitting in the µp atom are presented. An experimental configuration providing a sufficiently small muon stopping volume at the lowest pressures has been tested. The first experimental indications for the existence of a long-lived 2s fraction at low pressure are discussed.     

V2CO2MXene从CO2/N2混合气体中选择性吸附CO2的第一性原理计算

二氧化碳作为温室气体中最重要的组成部分,其含量的变化将直接影响全球气候变化,在燃烧后气体中选择性捕获CO₂,对减缓因CO₂浓度过高引发的环境问题具有十分重要的意义.本文采用第一性原理计算的方法,研究了V₂CO₂ MXene材料对CO₂的选择性吸附性能.首先研究了不同官能团V₂CT_X MXene材料的结构和性质,发现V₂CO₂具有良好的稳定性.后研究了V₂CO₂对CO₂的吸附行为,结果表明,当CO₂被水平吸附时,V₂CO₂对CO₂气体分子的吸附能力较强且均满足在高性能吸附剂表面吸附CO₂的理想值(-0.42 eV-0.82 eV),可以适用于探测/捕获CO₂气体分子.此外,进一步研究了相同条件下V<...