Emission of neutrino pairs by an electron in an ultrastrong magnetic field

The transitions of relativistic electrons in a magnetic field with the emission of an antineutrino-neutrino pair are considered. Probabilities are obtained for electron transitions to the ground state and weakly excited states. It is shown that in the case of an ultrastrong magnetic field (HH_o=m²c³/e=4.41·10¹³ G) such transitions made a considerable contribution to the total probability of the process.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 110–114, March, 1978.In conclusion, the authors express their profound gratitude to A. A. Sokolov for his attention to our work.     

High-temperature infrared spectrum of HCN near 3300 cm−2

The infrared absorption of HCN near the fundamental band at 3311 cm^?1 has been measured at temperatures up to 1200 K. Transitions involving high rotational states (up to J = 62) have been measured. These give an improved value for the sextic centrifugal distortion term H₀. Many hot-band transitions have been observed and assigned to transitions originating in vibrationally excited states up to 4000 cm^?1 above the ground state. These measurements give new data on vibrational states involving moderately high bending quantum numbers and indicate that new terms are needed to fit the ro-vibrational energy levels.     

The b-type rotational transitions of HNCO in the lowest excited vibrational state

In the microwave and millimeter wave spectra of HNCO, the b-type transitions between the K_a = 0 and 1 levels in the lowest excited vibrational state have been observed. Because of strong a-type Coriolis resonances among the three bending excited states the energy difference between the levels for K_a = 0 and 1 is much smaller in the lowest excited state than in the ground state. The subband origin of these b-type transitions has been found in the millimeter wave region at 275 697.309 MHz (9.1963 cm^?1). The effect of the Coriolis resonances is discussed in relation to the molecular quasi-linearity and is compared with the case of HNCS.     

Multiphoton mass spectra of XeKr molecules in the range of excited Xe*6<Emphasis Type="Italic">p</Emphasis>[5/2]<Subscript>2, 3</Subscript> atoms

Data on excited states of XeKr molecules in the energy range 78280–77600 cm^?1 are obtained. Using the method of multiphoton laser photoionization of molecules in a supersonic jet, five vibrational progressions of XeKr molecules are obtained, which are attributed to five electronic-vibrational transitions from the ground state of the XeKr molecule of the symmetry 0⁺ to excited states of the symmetry Ω = 0⁺, 1, 2 with the dissociation limit Kr¹ S ₀ + Xe*6p[5/2]₂ and of the symmetry Ω = 1, 2 with the dissociation limit Kr + Xe*6 p [5/2]₃. The molecular constants of the corresponding excited states of the XeKr molecule are estimated.     

Identification of a metastable state of the VZnH2 defect in ZnO

An infrared absorption study of the Zn vacancy passivated by two hydrogen atoms (V_ZnH₂) is reported. The ground state of the defect V_ZnH₂ consists of the inequivalent O–H bonds, which are aligned parallel and perpendicular to the c-axis, respectively. A metastable state of the defect was detected with two equivalent O–H bonds oriented perpendicular to the c-axis (V_ZnH₂^?). V_ZnH₂^? has two local vibration modes at 3329.0 and 3348.4 cm⁻¹ which are the antisymmetric and symmetric combinations of the two O–H stretch modes. The metastable state of the defect is 75±9 meV above the ground state of V_ZnH₂. An activation energy of 0.96±0.12 eV for the transition from metastable to the ground state was determined.     

Photoluminescence of concentration series of CaF2: Mn phosphors excited by VUV radiation

Fluorescent characteristics of a series of powder CaF₂: Mn phosphors (from 0.01 to 2.47 wt. % of Mn in the mixture) excited by VUV radiation with quantum energies up to 14 eV at 293 K and up to 12 eV at 85 K are measured. Narrow excitation bands of Mn²⁺ centers found at 7.9 and 8.6 eV (at 293 K) are assigned to partially forbidden transitions of electrons from the ground state ⁶ S split by the crystalline field (10 Dq=0.71 eV from the literature) in two sublevels to the excited level corresponding to the ⁶ D term of a free Mn²⁺ ion (3d ⁵ → 3d ⁴4s transitions). A wide nonelementary excitation band in the region of 9.1–10.3 eV is interpreted as photogeneration of near-activator D-excitations: allowed transitions of electrons from levels that are split from the top of the valence band under the influence of an impurity ion to the free 4s-orbital of a Mn²⁺ ion. Channels of energy transport in the CaF₂: Mn system are briefly analyzed.     

Fluorescence and fluorescence excitation spectra of jet-cooled carbazole

The fluorescence excitation spectra of jet-cooled carbazole molecules at vibrational temperatures of 55 and 80 K and the fluorescence spectrum of these molecules excited by radiation at the frequency of a pure electronic transition are measured. As the vibrational temperature increases, the excitation spectra exhibit a series of lines of the same symmetry, which are caused by the interaction of the active vibration with a subensemble of optically inactive vibrations. The final symmetry of the totally and nontotally symmetric vibrations is determined from the shape of the rotational contours of the lines of vibronic transitions. The values of a decrease in the frequency of the nontotally symmetric vibrations in the first excited electronic state S ₁ due to their interaction with the electronic state S ₂ are calculated to be up to 100 cm^?1. The frequencies of the pure electronic transitions in the absorption and fluorescence spectra coincide with each other and are equal to 30809 cm^?1, the frequencies of vibrations in the ground state S ₀ exceeding the frequencies of the corresponding vibrations in the excited state S ₁. The degree of polarization of the integral fluorescence is determined for a series of vibronic transitions of the a ₁ and b ₂ final symmetry that are observed in the fluorescence excitation spectra, and the contribution of the intensity with the borrowed polarization θ_⊥ to the integral fluorescence is calculated. It is found that the intensity θ_⊥ is higher for the transitions of the b ₂ symmetry and can reach ≈50%.     

Threshold energy electron impact excitation of carbon dioxide and carbon disulphide

The threshold energy electron impact excitation spectra of CO₂ and CS₂ have been studied using the sulfur hexafluoride scavenger technique. The main results are triplet state excitation and autoionisation of negative ions associated with resonant excited states of the molecules. This confirms previous data concerning diatomic molecules. Furthermore, transitions such as ¹Π_g?X¹Σ_g⁺ and ¹Π_u?X ¹Σ_g⁺ are only weakly induced by low energy electrons, while the corresponding triplet excitations are probably more easily produced. Structures at 5.6, 6.1 and 6.6 eV observed in CS₂ are due to negative ions and/or to ³Π_u, ³Π_g excitation.The autoionisation of CO₂^?(X²Π_u) proceeds also by ejection of a thermal energy electron and leads to highly excited vibrational levels (3–5 eV) of the ground electronic state of CO₂.     

Multiphoton mass spectra of Xe2 molecules in the range of excited Xe*(6p, 5d) atoms

The (2 + 1) photoionization mass spectra of Xe₂ molecules are studied in a supersonic jet upon excitation by laser radiation in the energy range 80321.3–77821 cm^?1, corresponding to the dissociation of the Xe₂ molecule into atoms Xe(¹ S ₀) + Xe*(6p, 5d). Several vibrational progressions are observed, which are attributed to two-photon transitions of Xe₂ from the ground state to the excited states of the O ⁺ _g, 1_g, and 2_g symmetries. Based on the analysis of these progressions, the molecular constants of a number of excited states of Xe₂ are estimated.     

Quantum transitions of relativistic electrons in a superstrong magnetic field

The probability of emission of a hard γ-quantum in relativistic electron transitions to the ground (or near it) level in a magnetic field H ～ H₀ = m²c³/e₀? = 4.41 × 10¹³G is obtained. For the inverse transitions from these levels the cross-section of electron photoexitation is calculated.     

Excited state spin waves in ErFe2

Neutron inelastic scattering measurements on ErFe₂ reveal an unusual doubling of the two lowest energy spin wave branches over a wide temperature range. Crystal field calculations suggest that one member of each doublet is associated with transitions from the ground state of Er³⁺ to the first excited state, while the other is associated with transitions between excited states. The gapless acoustic mode appearing at high temperatures is identified as a propagating excited state spin wave.     

On the Energy of a “One-Dimensional” Two-Electron Atom

Based on the perturbation theory and variational method long known for a “three-dimensional” atom, the ground and first excited state energies are calculated for a “one-dimensional” two-electron atom in the “one-dimensional ortho-helium” configuration, which can be obtained experimentally in principle, as has been already done for a Na Bose condensate, or produced in a super strong magnetic field B ? (2α)²B₀ (B₀ = m²c³/e? ≈ 4.41 × 10¹³ G). The “screening constant” σ for this atom in the ground and excited states was about 0.20 and 0.17, 0.18, respectively, depending on the relative parity PP' of the electronic states, which is somewhat smaller than in “two-dimensional” and “three-dimensional” variants (in these cases, this constant in the ground state is almost the same and about 0.3). The frequencies of the main spectral lines of a “onedimensional” He atom representing a doublet split over the relative parity PP' are found. The presence of the close lines of this doublet in the emission spectrum of magnetars at frequencies ω_{1, 2} ≈ {1.15; 1.17}α²(c/λC) (α = e²/?c, λ_C =?/mc) corresponding to the “one-dimensional ortho-helium” would suggest the existence of a superstrong magnetic field in such astrophysical objects.     

The laser-induced fluorescence spectroscopy of gold monoxide: B2Σ−－X2Π3/2 transition

The electronic spectrum of the gaseous gold monoxide molecule has been investigated in the range of 16000－18500?cm^?1 using laser induced fluorescence spectroscopy and single vibronic level emission spectra. Five rotationally resolved vibronic bands are observed and assigned to the transitions B²Σ^? (v'?=?0－4) －X²п_3/2 (v''?=?0), in which the 0－0 transition is observed for the first time. The molecular constants of the excited state B²Σ^? are obtained by a rotational analysis of the spectra. The spin-orbit coupling constant and the vibrational constants of the ground state X²п_i are determined with the accuracy improved by one order of magnitude. The lifetimes of most observed bands are also measured for the first time.     

Levels in 156Gd studied in the (n, γ) reaction

Levels up to 2.3 MeV in ¹⁵⁶Gd have been studied using the (n, γ) reaction. Energies and intensities of low-energy γ-rays and electrons emitted after thermal neutron capture have been measured with a curved-crystal spectrometer, Ge(Li) detectors and a magnetic electron spectrometer. High-energy (primary) γ-rays and electrons have been measured with Ge(Li) detectors and a magnetic spectrometer. The high-energy γ-ray spectrum has also been measured in thermal neutron capture in 2 keV resonance neutron capture. The neutron separation energy in ¹⁵⁶Gd was measured as S_n = 8535.8 ± 0.5 keV.About 600 transitions were observed of which ~50% could be placed in a level scheme containing more than 50 levels up to 2.3 MeV excitation energy. 42 of these levels were grouped into 15 excited bands. In addition to the β-band at 1050 keV we observe 0⁺ bands at 1168, 1715 and 1851 keV. Other positive-parity bands are: 1⁺ bands at 1966, 2027 and 2187 keV; 2⁺ bands at 1154 (γ-band) and 1828 keV; and 4⁺ bands at 1511 and 1861 keV. Negative-parity bands are observed at 1243 keV (1^?), 1366 keV (0^?), 1780 keV (2^?) and 2045 keV (4^?). Reduced E2 and E0 transition probabilities have been derived for many transitions. The ground band, the β- and γ-bands and the 0⁺ band at 1168 keV have been included in a phenomenological four-band mixing calculation, which reproduces well the experimental energies and E2 transition probabilities.The lowest three negative-parity (octupole) bands of which the 0^? and the 1^? bands are very strongly mixed, were included in a Coriolis-coupling analysis, which reproduces well the observed energies. The E1 transition probabilities to the ground band are also well reproduced, while those from the higher-lying 0⁺ bands to the octupole bands are not reproduced. Absolute and relative transition probabilities have been compared with predictions of the IBA model and the pairingplus-quadrupole model. Both models reproduce well the E2 transitions from the γ-band, while strong disagreements are found for the E2 transitions from the β-band. The IBA model predicts part of the decay features of the higher lying 2⁺₂, 4⁺₁ and 2^?₁ bands.     

Deexcitation of Cd 53P1 atoms in collisions with ground state atoms and molecules

Collisions of excited Cd 5³P₁ atoms were investigated using atomic fluorescence spectroscopy. Cadmium vapor, together with a quenching gas, was irradiated in a quartz fluorescence vessel with Cd 3261 Å resonance radiation and the intensity of the resulting resonance fluorescence was monitored in relation to the gas pressures. The experiments yielded the following cross sections Q₁₀ (in A²) for collisional transfer 5³P₁→5³P₀: CdAr=2×10^?3, CdN₂=8.0, CdH₂=7.0, CdCO=15.6. The cross sections Q for collisional deexcitation to the ground state (quenching) in A² are CdN₂ = 2.6×10^?2, CdH₂ = 11.0, CdCO = 3.4, CdCO₂ = 26.     

Formation of intersystem crossing transitions in Pd(II) and Pt(II) porphyrins: Nonplanar distortions of the macrocycle and charge transfer states

We found new bands in the absorption spectra of Pt(II) and Pd(II) complexes of octaethylporphyrin and tetraphenylporphyrin that differ in the nature, number, and position of their side substituents. The bands are observed at 295 K in the range 570–690 nm and are attributed to spin-forbidden transitions from the ground S ₀ state to the excited T ₁ and T ₂ triplet states (the internal heavy atom effect). We determined the frequency distribution, number, and nature of these transitions, as well as their extinction coefficients (? = 6.0–210.0 M^?1 cm^?1), using computer decomposition of complex contours into Gaussian components and additional data obtained from the phosphorescence and phosphorescence excitation spectra of these complexes (295–77 K). In comparison to Pd complexes of porphyrins with planar macrocycles, nonplanar distortions of the tetrapyrrole macrocycle in the ground S ₀ state of the sterically hindered PdOETPP molecule cause a bathochromic shift of the bands of the electronic spin-forbidden S ₀ → T ₁ and S ₀ → T ₂ transitions, as well as an increase in their extinction coefficients. For the PdOEP-Ph(o-NO₂) molecule, which contains the electron acceptor nitro group, an absorption band attributed to an electronic transition from the ground state S ₀ to a charge transfer state (λ_max = 905 nm, ? = 10.0 M^?1 cm^?1) is observed at 295 K.     

Millimeter- and submillimeter-wave length spectrum of the partially deuterated ammonias; A study of inversion,centrifugal distortion,and rotation-inversion interactions

Eighty-two new rotation-inversion transitions of the light asymmetric rotors NH₂D and ND₂H have been measured in the 80–600 GHz region by means of high resolution microwave techniques. Included among these transitions are several submillimeter R-branch transitions which make possible a calculation of both the rotational and distortion parameters which characterize the molecule. An accurate inversion Hamiltonian is developed and used as a preliminary step to a rotation-distortion treatment of the molecule. The spectrum of ND₂H reveals the existence of a rotation-vibration interaction which significantly alters the energy of a number of ground vibrational state levels. The results of an analysis technique which incorporates the effects of this perturbation as well as the inversion effects are presented. This procedure makes possible the analysis of all observed transitions to within experimental uncertainties as well as the accurate prediction of unobserved transitions. The rotational constants which result from this work are (MHz): For NH₂D, O⁺ vibrational state,a= 290 286.53 ± 0.21,B= 192 240.15 ± 0.42,C= 140 602.50 ± 0.42; for NH₂D, O^? vibrational state,a= 290 192.14 ± 0.21,B= 192 176.27 ± 0.42,C= 140 625.64 ± 0.42; for ND₂H, O⁺ vibrational state,a= 223 222.92 ± 0.18,B= 160 433.96 ± 0.17,C= 112 305.40 ± 0.17; for ND₂H, O^? vibrational state,a= 223 147.21 ± 0.14,B= 160 423.37 ± 0.13,C= 112 313.72 ± 0.13.     

Conformation and dipole moment of tetrahydropyran-4-one by microwave spectroscopy

The microwave spectrum of tetrahydropyran-4-one has been studied in the frequency region 18 to 40 GHz. The rotational constants for the ground state and nine vibrationally excited states have been derived by fitting a-type R-branch transitions. The rotational constants for the ground state are (in MHz) A = 4566.882 ± 0.033, B = 2538.316 ± 0.003, C = 1805.878 ± 0.004. From information obtained from the gas-phase far-infrared spectrum and relative intensity measurements, these excited states are estimated to be ～ 100 cm^?1 above the ground state for the first excited state of the ring-bending and ～ 185 cm^?1 for the first excited state of the ring-twisting mode. Stark displacement measurements were made for several transitions and the dipole moment components determined by least-squares fitting of the displacements: (in Debye) |μ_a| = 1.693 (0.001), |μ_b| = 0.0, |μ_c| = 0.300 (0.013) yielding a total dipole moment μ_tot = 1.720 (0.003). A model calculation to reproduce the rotational parameters indicates that the data are consistent with the chair conformation.     

Nuclear reactions as an example of the quantum theory of irreversible processes

A modification of the atomic beam magnetic resonance method for investigation of the hyperfine structure of excited atomic states will be described. Radiofrequency transitions between the hyperfine structure niveaus of the excited state, which are unequally populated by circularly polarized light, are detected by observing the resulting change in population number of the hyperfine structure niveaus of the ground state using magnetic deflection in an inhomogeneous field and additional radiofrequency transitions in the ground state as analyzers. As an application the hyperfine structure of the excited 4² P _3/2-state of K³⁹ has been investigated in an almost strong magnetic field of about 65 G with a constant frequency of the applied radiofrequency field of 125.50 Mc/s. The analysis of the radiofrequency signal of the excited state detected as a change in the amplitude of a radiofrequency transition in the ground state yielded the valuesA=(6.10±0.25) Mc/s andB=(1.8±1.2) Mc/s for the hyperfine structure constants of the 4² P _3/2-state of K³⁹. Further possibilities for observing signals of the excited state with the apparatus used in this experiment are also discussed.     

H2(X1∑g+)—H2(E1∑g+)系统的相互作用

采用显含电子对相关坐标的波函数,在微扰论的框架下计算了E^l∑_g⁺态氢分子与基态氢分子取cross构型时的中长程相互作用。结果表明,该相互作用在分子间距6.5α₀附近存在着一个活化能势垒,在4.5α₀附近显示出较强的化学键行为。 关键词：