Synthesis and Fluorescence Properties of Lanthanide (III) Perchlorate Complexes with Naphthyl-Naphthalinesulphonylpropyl Sulfoxide

A ligand with double sulfinyl groups, naphthyl-naphthalinesulphonylpropyl sulfoxide(dinaphthyl disulfoxide, L), was synthesized by a new method and its several lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DTA, ¹HNMR and UV spectra. The composition of these complexes, were RE₂(ClO₄)₆·(L)₅·nH₂O (RE = La, Nd, Eu, Tb, Yb, n = 2 ∼ 6, L = C₁₀H₇SOC₃H₆SOC₁₀H₇). The fluorescent spectra illustrated that the Eu (III) complex had an excellent luminescence. It was supposed that the ligand was benefited for transferring the energy from ligand to the excitation state energy level (⁵D₀) of Eu (III). The Tb (III) complex displayed weak luminescence, which attributed to low energy transferring efficiency between the average triplet state energy level of ligand and the excited state (⁵D₄) of Tb (III). So the Eu (III) complex displayed a good antenna effect for luminescence. The phosphorescence spectra and the relationship between fluorescence lifetime and fluorescence intensity were also discussed.     

Penning ionization electron spectroscopy of H2O,D2O,H2S and SO2

Electron energy peak shifts and peak shapes were determined in the ionization of H₂O, D₂O, H₂S and SO₂ by Ne(³P₂) and He(2¹S, 2³S) metastable atoms. The shifts are large, especially in ionization of H₂O and D₂O into the ionic ground state and are probably mostly due to chemical interaction during the collision.In a previous paper the electron energy distribution curves for ionization of CO, HCl, HBr, N₂O, NO₂, CO₂, COS and CS₂ by helium, neon and argon metastables and the characteristics of this ionization were described¹. In this paper the series of triatomic molecules was extended to the molecules H₂O, D₂O, H₂S and SO₂. Because all these molecules have considerable dipole moments it could be expected that the peak shifts might be enhanced as compared with other triatomic molecules.     

Cation spectroscopy of 3,4-difluoroaniline by two-color resonant two-photon mass-analyzed threshold ionization

We applied the two-color resonant two-photon mass-analyzed threshold ionization technique to record the vibrationally resolved cation spectra of 3,4-difluoroaniline (34DFA) via the 0⁰, X¹, 6b¹, and I² levels of the S₁ state. The adiabatic ionization energy of this molecule was determined to be 64 195 ± 5 cm⁻¹. Most of the observed active modes of the 34DFA cation in the D₀ state are related to the in-plane ring deformation vibrations. Comparing these data with those of 3-fluoroaniline and 4-fluoroaniline, one can learn the effects of fluorine substitution on the electronic transition and molecular vibration.     

Synthesis and Fluorescence Properties of Lanthanide (III) Perchlorate Complexes with Bis(benzoylmethyl) Sulfoxide

A ligand with two carbonyl groups and one sulfinyl group has been synthesized by a new method and its several lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, ¹H NMR and UV spectra. The results indicated that the composition of these complexes is REL₅(ClO₄)₃·3H₂O (RE = La(III), Pr(III), Eu(III), Tb(III), Yb(III), L = C₆H₅COCH₂SOCH₂COC₆H₅). The fluorescent spectra illustrate that both the Tb (III) and Eu (III) complexes display characteristic metal-centered fluorescence in solid state, indicating the ligand favors energy transfer to the excitation state energy level of them. However, the Tb (III) complex displays more effective luminescence than the Eu (III) complex, which is attributed to especial effectively in transferring energy from the average triplet energy level of the ligands (T) onto the excited state (⁵D₄) of Tb (III) than that (⁵D₀) of Eu (III), showing a good antenna effect for Tb(III) luminescence. The phosphorescence spectra and the relationship between fluorescence lifetimes and fluorescence intensities were also discussed.     

Theoretical investigation of the ultrafast NeNePo spectroscopy of Au 4 and Ag 4 Clusters

Ultrafast ground state nuclear dynamics of Au₄ and Ag₄ is theoretically explored in the framework of negative ion - to neutral - to positive ion (NeNePo) pump-probe spectroscopy based on the ab initio Wigner distribution approach. This involves the preparation of a nonequilibrium neutral ensemble by pump induced photodetachment of a thermal anionic ground state distribution, gradient corrected DFT classical trajectory simulations “on the fly” on the neutral ground state, and detection of the relaxation process of the ensemble in the cationic ground state by a time-delayed probe pulse. In Au₄, the initially prepared linear structure is close to a local minimum of the neutral state giving rise to characteristic vibrations in the signals for probe wavelength near the initial Franck-Condon transition. A timescale of ∼1 ps for the structural relaxation towards the stable rhombic D_2h neutral isomer was determined by the increase of the signal for probe wavelength in vicinity of the vertical ionization energy of the rhombic structure. In contrast, the relaxation dynamics in Ag₄ is characterized by normal mode vibrations since both the initially prepared anionic ground state and the neutral ground state have rhombic minimum geometries. Thus, time-resolved oscillations of pump-probe signals are fingerprints of structural behaviour which can be used experimentally for the identification of particular isomers in the framework of NeNePo spectroscopy. Received 22 December 2000     

REMPI as a tool for studies of OH radicals in catalytic reactions

2 +? O₂→H₂O on polycrystalline Pt foils has been studied by detection of desorbing OH radicals using the Resonance Enhanced Multiphoton Ionization, REMPI, technique. The measurements were performed at catalyst temperatures of 1000–1400 K and a total pressure below 10^-4 mbar. The studies of OH desorption by REMPI were achieved using a two-photon excitation D²Σ^-–X²Π (1–0), followed by one-photon ionization. The ions were detected in a time-of-flight mass spectrometer, TOF-MS, in order to avoid interference from non-resonantly ionized molecules. By applying TOF-MS, a simultaneous non-resonant ionization and detection of H₂, O₂ and H₂O was achieved. Recorded REMPI spectra were compared with spectra simulated using known molecular constants. The kinetics of the reaction derived from the measurements were compared with what was obtained in earlier LIF detection of OH, performed at higher total reactant pressure using the A–X transition. REMPI TOF-MS is shown to be a complement to LIF for reaction studies below 5×10^-4 mbar total pressure, where LIF is too insensitive for quantification. The reaction kinetics was found to be in agreement with a theoretic model and previous LIF studies. Received: 8 March 1996/Revised version: 4 October 1996     

从头计算研究CH3C(O)OSSOC(O)CH3的构型和能量

采用从头计算B3LYP,MP3和MP4方法结合Aug-cc-pVDZ基组研究了CH₃C(O)OSSOC(O)CH₃最稳定的五种构象及其阳离子构型.理论计算了五种稳定构象的转动常数和偶极矩;运用电子传播子理论P3近似方法计算稳定构象外价壳层轨道的电离能,计算结果与光电子能谱实验结果符合的较好.根据构象的相对能量以及理论模拟电离能谱和实验光电子能谱之间的比较,说明在气相光电子能谱实验中至少存在两种构象.与中性构型相比,电离后的五种阳离子构型均发生了明显的结构弛豫,尤 关键词： 构象 电离能 相对能量 光电子能谱     

Experimental determination of the electron screening potential energy for the d(d, n)3He Reaction in ZrD2 and D2O in the ultralow energy region

This work is devoted to measuring of the values of the astrophysical S-factors and electron screening potential energy for a d(d,n)³He reaction occurring at ultralow energies in zirconium deuteride ZrD₂ (3.5–7.0 keV) and heavy water D₂O (2.2–6.0 keV). The experiment was performed on the Hall pulsed plasma accelerator at the TPU Nuclear Physics Institute (Tomsk) with ZrD₂ and D₂O targets produced by the magnetron sputtering of zirconium in a deuterium environment and heavy water freezing-out on a copper support, respectively. A χ ² analysis of the dependence of the neutron yields and astrophysical S-factors for the dd reaction on the deuteron collision energy E revealed that the upper bounds of the electron screening potential energy for interacting deuterons in ZrD₂ and D₂O and of the astrophysical S-factors at the deuteron collision energy E = 0 were U _e (ZrD₂) < 30 eV, U _e (D₂O) < 25 eV, S(0) = (57.2 ± 3.9) keV · b (ZrD₂), S(0) = (58.6 ± 3.6) keV · b (D₂O) at the 90% confidence level.     

Mass analyzed threshold ionization of hydrogen bonded clusters of biological molecules: the 3-methylindole·C6H6 complex

The mass analyzed threshold ionization (MATI) technique has been used for measuring the adiabatic ionization energy of the 3-methylindole·C₆H₆ cluster (58 018 cm⁻¹) and the binding energies in its ground ionic (4448 cm⁻¹) and ground neutral state (1775 cm⁻¹). We compare our results with those recently obtained for the 3-methylindole·H₂O and the indole·C₆H₆ cluster. The small influence of methylation on the binding energies confirms the πhydrogen bonding character in the 3-methylindole·C₆H₆ complex.     

Theoretical insight into the excited‐state behavior of a novel Compound 1: A TDDFT investigation

In the present work, using density functional theory and time‐dependent density functional theory methods, we investigated and presented the excited‐state intramolecular proton transfer (ESIPT) mechanisms of a novel Compound 1 theoretically. Analyses of electrostatic potential surfaces and reduced density gradient (RDG) versus sign(λ₂)ρ, we confirm the existence of intramolecular hydrogen bond O1‐H2···N3 for Compound 1 in the S₀ state. Comparing the primary structural variations of Compound 1 involved in the intramolecular hydrogen bond, we find that O1‐H2···N3 should be strengthened in the S₁ state, which may facilitate the ESIPT process. Concomitantly, infrared (IR) vibrational spectra analyses further verify the stability of hydrogen bond. In addition, the role of charge transfer interaction has been addressed under the frontier molecular orbitals, which depicts the nature of electronical excited state and supports the ESIPT reaction. The theoretically scanned and optimized potential energy curves according to variational O1‐H2 coordinate demonstrate that the proton transfer process should occur spontaneously in the S₁ state. It further explains why the emission peak of Compound 1‐enol was not reported in previous experiment. This work not only presents the ESIPT mechanism of Compound 1 but also promotes the understanding of this kind of molecules for further applications in future.     

Fast decay of high vibronic S1 states in gas-phase benzene

Lifetimes of different vibronic levels at high excess energies in the S₁ state of isolated benzene molecules are measured using for the first time a two-photon ionization pump–probe technique with UV femtosecond pulses. For the 6¹1³ state (3290 cm^-1 excess energy) at the onset of the ‘channel three’ a biexponential decay is found with a fast (τ_f=20 ps) and a slow (τ_s>500 ps) component. The values are in line with previous sub-Doppler high-resolution measurements of this band in our laboratory. We explain the measured faster decay (τ_f=900 fs, τ_s=100 ps) of the 7¹ state at a lower excess energy of 3077 cm^-1 by a simultaneous excitation of the adjacent 6¹ ₀1³ ₀16¹ ₁ hot band leading to a vibronic state of higher excess energy and faster decay. The vibronic levels 6¹1⁴ and 7¹1¹ at a higher excess energy of ≳4000 cm^-1 show a biexponential decay of τ_f=550 fs, τ_s=30 ps and τ_f≲300 fs, τ_s=20 ps, respectively. The experimental results point to dynamic processes within the vibronic level manifold of the S₁ state and a fast nonradiative electronic relaxation process. Received: 3 November 1999 / Published online: 5 July 2000     

Pulsed-laser photolysis of Mn2(CO)10: A time-resolved fluorescence study

Mn₂(CO)₁₀ was photolysed in the gas phase by the XeCl-excimer laser with fluence in the range 25–300 mJ/cm² and a dye laser. The UV/VIS emission of the products was probed on a nanosecond time scale. The emission from excited states of metal atoms was detected only. The Mn atoms are predominantly formed in their ground statea ⁶ S _{2 1/2}. The absorption of one photon and the subsequent relaxation process leads to the formation ofz ⁶ P _J ⁰ (J = 11/2, 21/2, 31/2) states and emission of photons at a wavelength of 403 nm. The formation of the excited statese ⁸ D _{5 1/2},z ⁶ F _{4 1/2} ⁰ ande ⁶ D _{4 1/2} and the subsequent emission observed at wavelengths of 357, 383 and 446 nm requires the absorption of two photons by the ground-state Mn atoms. In addition, transition from thea ⁶ D _j (J = 11/2, 21/2) lower states were observed in the wavelength-resolved Laser-Induced Fluorescence (LIF) spectra.     

Characters of the irreducible nonequivalent loaded corepresentations of some point groups

We present tables of the characters of the irreducible nonequivalent loaded corepresentations of the point groups C₀, C₂, S₂, C_h, C₃, C₄, S₄, C_2v, C_2h, D₂ C₆, S₆, C_3h, C_3v, D₃, C_4h, C_4v, D₄, D_2d, C_6h C_6v, D_3d. D₆, D_3h, T, T_h, T_d O and O_h.Translated from Izvestiya VUZ. Fizika, Vol. 11, No. 11, pp. 23–34, November, 1968.     

Die Eigenschwingungen des Metall-Hydratkomplexes in BeSO4·4H2O und BeSO4·4D2O

Infrared reflection spectra of single crystals of BeSO₄·4H₂O and BeSO₄·4D₂O have been obtained in polarized light at 300°K and at 14°K in the region between 4000 cm^?1 and 300 cm^?1. By a Kronig-Kramers analysis, the frequencies of the infrared active transitions have been calculated. These transitions are attributed to internal vibrations of the water molecules and sulfate ions and, in the region between 1000 cm^?1 and 300 cm^?1, especially to internal and external vibrations of the tetrahedral Be⁺⁺·4aqu-complexes. The vibrational modes of these complexes consist of a superposition of translational and librational modes of the water molecules and translational modes of the central Be⁺⁺-ion. The vibrational frequencies and normal modes of this complex have been calculated in a central-force model, and force-constants have been determined by fitting the calculated frequencies to the observed spectra. The calculations have shown that the modes, which comprise mainly translational motions of the water molecules, are strongly coupled with librational motions of the water molecules. On the other hand, there exist pure librational modes with practically no admixture of translational motions. The optimum sets of force constants for the BeSO₄·4H₂O crystal and the BeSO₄·4D₂O crystal differ in a manner which can be understood under the assumption that the dimensions of the Be(D₂O)₄ complex are about 0.1 Å larger than those of the Be(H₂O)₄ complex. Some arguments supporting this conclusion will be discussed.     

Vibronic and cation spectroscopy of m-chloroaniline

We applied the resonant two-photon ionization and mass-analyzed threshold ionization spectroscopic techniques to record the vibronic and cation spectra of m-chloroaniline. The band origin of the first electronic transition was found to be 33 658 ± 2 cm⁻¹, whereas the adiabatic ionization energy was determined to be 63 958 ± 5 cm⁻¹. Within our experimental detection limit, these measured values are the same for both of the ³⁵Cl and ³⁷Cl isotopomers. The observed active modes of this molecule in the electronically excited S₁ and cationic ground D₀ states mainly involve the in-plane ring deformation and substituent-sensitive bending vibrations.     

Investigation of highly excited states of calcium by three-photon ionization

The three-photon ionization in Ca from S₀ ground state is studied. The two-photon process is a near -- resonance process with one of the following bound states: 4s4d ¹D₂, 4p P₂, 4s6s ¹S₀, 4 D₂ and 4 S₀ while the third photon reach either directly the continuum or one of the autoionizing states. The succession of bound states as well as the transitions above the ionization limit are discussed. The dynamics of the multiphoton excitation processes is also discussed and radiative decay of 4 S₀ Ca state with two-photon excitation as well as (the measured) decay times of the Ca autoionizing states using the proper line profiles for different quantum numbers has been determined.Received: 29 September 2003, Published online: 18 May 2004PACS: 32.70.-n Intensities and shapes of atomic spectral lines - 32.70.Cs Oscillator strengths, lifetimes, transition moments - 32.80.Fb Photoionization of atoms and ions - 32.80.Rm Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)     

Measurements of photoionization cross sections from the 4p, 5d and 7s excited states of potassium

New measurements of the photoionization cross sections from the 4p ²P_1/2,3/2, 5d ²D_5/2,3/2 and 7s ²S_1/2 excited states of potassium are presented. The cross sections have been measured by two-step excitation and ionization using a Nd:YAG laser in conjunction with a thermionic diode ion detector. By applying the saturation technique, the absolute values of the cross sections from the 4p ²P_3/2 and 4p ²P_1/2 states at 355 nm are determined as 7.2±1.1 and 5.6±0.8 Mb, respectively. The photoionization cross section from the 5d ²D_5/2,3/2 excited state has been measured using two excitation paths, two-step excitation and two-photon excitation from the ground state. The measured values of the cross sections from the 5d ²D_5/2 state by two-photon excitation from the ground state is 28.9±4.3 Mb, whereas in the two-step excitation, the cross section from the 5d ²D_3/2 state via the 4p ²P_1/2 state and from the 5d ²D_5/2,3/2 states via the 4p ²P_3/2 state are determined as 25.1±3.8 and 30.2±4.5 Mb, respectively. Besides, we have measured the photoionization cross sections from the 7s ²S_1/2 excited state using the two-photon excitation from the ground state as 0.61±0.09 Mb.     

Deuterium separation by multiphoton dissociation of dichlorofluoromethane

Absorption and dissociation probabilities of CHCl₂F and CDCl₂F were investigated by a pulsed CO₂ laser in the wavenumber region of largest selectivity for deuterium. The absorption of CHCl₂F, which is a difference band, can largely be suppressed by cooling. At 200 K and at 920 cm^–1 absorption selectivities up to 4000 were found by extrapolation. In the presence of buffer gas, CDCl₂F can be multiphoton excited nearly like a linear absorber (harmonic oscillator). This is interpreted by a nearly resonant collisional relaxation v₇ to v₂ and by the smallness of the cross anharmonicity x₂₇. The dissociation selectivityS was 24,000 at natural abundance. Such large values were measured by a chromatographic method.S depends only onp _D, the partial pressure of the deuterated species. This dependence is approximately ln Sp _D ^–1 . It can be rationalized by considering only the average energy transferred to the nonresonant molecules by collisions with CDCl₂F. The above functional shape is related to an Arrhenius type law. Comparison with trifluoromethane for D separation shows that CHCl₂F has primarily two advantages: its rapid H-D exchange with water and the less stringent requirements of laser energy and pulse length.A preliminary account of this work has appeared in Quantum Electr.2, 13 (1985) (in Chinese)     

A theoretical study of the Y$\mathsf{_{3}}$O clusters

Hybrid density functional calculations are performed to study the structural and electronic properties of neutral, anionic and cationic Y₃O clusters. The most stable structures of these clusters are found to be triply bridging oxygen atom structures with C_S symmetry. The ground states of Y₃O, Y₃O^- and Y₃O ⁺ are doublet (²A), triplet (³A) and singlet (¹A), respectively. The calculated electron affinities and ionization potentials are in good agreement with the available experimental data. Time-dependent density functional theory is used to calculate the low-lying excited states. A theoretical assignment for the features in the experimental photoelectron spectra is given.Received: 5 November 2003, Published online: 20 January 2004PACS: 36.40.Mr Spectroscopy and geometrical structure of clusters - 31.15.Ew Density-functional theory - 34.50.Gb Electronic excitation and ionization of molecules; intermediate molecular states (including lifetimes, state mixing, etc.)     

Structure of ZnZrF<Subscript>6</Subscript> · <Emphasis Type="Italic">n</Emphasis>H<Subscript>2</Subscript>O (<Emphasis Type="Italic">n</Emphasis> = 6–2) and ZnZrF<Subscript>6</Subscript> crystallohydrates according to vibrational spectroscopy data

Fluoridezirconate crystallohydrates ZnZrF₆ · nH₂O (n = 6–2) and anhydrous ZnZrF₆ are investigated by vibrational spectroscopy and thermography. The influence of the hydrate number on the structure of the cationic and anionic sublattices of the crystallohydrates is studied. The changes in the strength of HOH···F and HOH···O hydrogen bonds of coordinated and outer-sphere water molecules occurring with variations in the hydrate number are determined by changes in the IR spectra. The IR spectra of ZnZrF₆ · nH₂O (n =6, 4) compounds, which have isolated complex anions [ZrF₆]^2– in their structure, revealed a band with two peaks in the range of 3470–3430 cm^–1, which corresponds to stretching vibrations of coordinated water molecules. The spectra of ZnZrF₆ · nH₂O (n = 5, 3, 2, 1) crystallohydrates with a polymeric structure show a high-frequency shift of this band, which corresponds to weakening of hydrogen bonds. The vibrations of crystallization water molecules involved in the network of strong O–H···F and O–H···O hydrogen bonds manifest themselves in the spectra of ZnZrF₆ · nH₂O (n =5, 3) crystallohydrates by broad structureless bands in the region of stretching, bending, and libration vibrations.