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1.
Molecular structures and energies have been calculated in the MNDO approximation, for P4S3 and its molecular ion P4S3+, and for the mass spectral fragment pairs: (P3S3+ + P), (P3S2+ + PS), (P3S+ + PS2), (P2S3+ + P2), (P2S2+ + P2S), (P2S+ + P2S2), (P2S2), PS3+ + P3), (PS2+ + P3S), (PS+ + P3S2), and (PS+ + P2S + PS). Three distinct energy minima were found for each of P2S2+ and P2S2, and two minima for each of P2S+, P2S, PS3+, PS3+, PS2+, PS2, P3+ and P3. The fragments arising from P4 and P4+ were also investigated. The structures are discussed in terms of the Jahn—Teller effect, whose predictions are fulfilled without exception. 相似文献
2.
Structures and enthalpies of formation have been calculated, in the MNDO approximation using UHF wave-functions for open shell species, for tetramethyldiphosphine, Me4P2, and the major ions in its mass spectrum: Me4P2+, Me3P2H+, Me3P2+, Me2P2H2+ (3 forms), Me2P2H+ (3 forms), Me2P2+ (3 forms), MePPCH2+ (3 forms), MeP2+ and MePCH2+, together with all the corresponding neutral fragments. Appearance potentials are calculated for all the ions, and possible fragmentation pathways deduced. 相似文献
3.
The reaction of Kr+(2P3/2) and Kr+(2P1/2) with H2 are examined using a conventional ICR and a tandem Dempster- ICR instrument. The accidentally near-resonant charge-transfer reaction of CO+ with Kr was used to prepare a nearly pure 2P3/2 state Kr+ beam to evaluate rates of reaction of the 2P3/2 and 2P1/2 state with H2. It was found that the Kr+(2P3/2) reacts faster than the Kr(2P1/2) and a negligible activation energy exists for both reactions. 相似文献
4.
G. Haeffler U. Ljungblad I. Yu. Kiyan D. Hanstorp 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,42(4):263-266
The energies of the As? fine structure components 4p4 3 P 1 and 4p4 3 P 0 have been determined relative to the 4p4 3P2 ground state by using photodetachment electron spectroscopy. Fine structure splittings of ΔE(3 P 1 ? 3 P 2) = 125(3) meV and ΔE(3 P 0 ? 3 P 2) = 166(5) meV have been obtained. It is the first experimental determination of the energy of the J = 1 level and an improvement of the accuracy for the J = 0 level. Previous isoelectronic extrapolations are consistent with the experimental values. 相似文献
5.
《Chemical physics》1987,113(1):73-86
The spectra and kinetics observed following excitation of Hg 6s6p(1P1) in xenon show the occurence of complex attachment and relaxation processes. The 1P1 attaches to Xe in termolecular collisions to produce HgXe E11, which emits a broad band with λmax ≈ 2150 Å. Addition of krypton to Hg, Xe mixtures enhances the E-state emission by atom exchange with an HgKr* complex. The E state also undergoes collisional deactivation by Xe, rate coefficient (1.75 ± 0.25) × 10−11 cm3 molecule−1 s−1, to generate 3P2. However, the predominant route for 3P2 formation is via collision of 1P1 with Xe, rate coefficient ≈ 4 × 10−12 cm3 molecule−1 s−1. With [Xe] at 760 Torr, about 75% of the generated 3P2 is attached in the form of the HgXe(C 32) complex; lifetimes up to 600 μs have been observed. Two new emission bands occur when 3P2 is prepared in xenon. A sharp feature, slightly blue-shifted from the forbidden 3P2:1S0 line, results when 3P2 and Xe approach on the D 31 surface. The other band is broad with λmax ≈ 2520 Å; the carrier is assigned to an HgXe2(32u) complex. Rate coefficients for deactivation of 3P2 to lower 3PJ states have been measured. 相似文献
6.
Hiroshi Tatewaki Hirosiji Taketa Fukashi Sasaki 《International journal of quantum chemistry》1971,5(3):335-357
Wave functions of the 1S (ground state), 3P and 1P states for the beryllium isoelectronic sequence have been obtained in various approximations. The HF 2p orbitals for the 1P and 3P states are similar except for Be, where the 2p orbital is quite diffuse for the 1P state. The difference between the experimental E(1P) – E(3P) and the HF E(1P) – E(3P) is 0.62 eV for Be and 1.17 ~ 1.40 eV for B+ ~ F5+. The disagreements are attributed to the correlation effects between the 2s and 2p electrons. This is confirmed by ci calculations. It is shown that a limited basis SCF calculation reproduces the above feature of the HF results if we treat the orbital exponents as the variational parameters. The use of the Slater values for the orbital exponents is shown to be inadequate especially for the Be 1P state. The conclusions of this paper will be useful for discussing the V–T separations of H2 and C2H4. 相似文献
7.
P. H. Plesch 《Macromolecular Symposia》1990,32(1):299-306
The formation of complexes P+nM between a propagating carbenium ion P+n and the monomer, M, is considered from several points of view - (i) Under the most usual conditions the formation of the P+nM reduces the population of ion-pairs, P+nA−, drastically. This can account for the frequently found nil-effect of common ion salts on the rate of attack of carbenium ions on alkenes in initiation, model reactions, and polymerisations. - (ii) The formation of P+nM increases the degree of dissociation α of P+nA−, so that all the estimates of α on which kinetic schemes have been based, are too low. - (iii) The very high polymerisation rates found for n-donor monomers, say 4-MeO-styrene or N-vinylcarbazole compared to styrene, may be attributable not, primarily, to a difference in rate-constants, but to a difference in ionic population. This is because the fast P+nM is in greater excess over the slow P+nA− for more strongly complexing n-donors than for the π-donors. - (iv) Since the nature of the P+nM is different for every monomer, a comparison of their propagation rate-constants k+pM is hardly meaningful and valid comparisons can only be made between the k+p of the P+n. The measurement of these requires extreme conditions, either extrapolations to [P+n] = 0 and [M] = 0, or the use of highly polar solvents in which neither M nor the anion can compete with the solvent for the solvation of the P+n. 相似文献
8.
Jin‐Feng Sun Jie‐Min Wang De‐Heng Shi 《International journal of quantum chemistry》2012,112(3):672-682
The highly accurate valence internally contracted multireference configuration interaction (MRCI) approach has been employed to investigate the potential energy curves (PECs) for the X2Π, b4Σ?, C2Σ? states of PO and the X1Σ+ state of PO+. For these electronic states, the spectroscopic parameters of the isotopes (P16O, P18O, P16O+, and P18O+) have been determined and compared with those of the investigations reported in the literature. The comparison shows that excellent agreement exists between the present results and the available experiments. With the PECs determined here, the first 30 vibrational states for P16O(X2Π, b4Σ?), P18O(X2Π, b4Σ?), P16O+(X1Σ+), and P18O+(X1Σ+) are computed when the rotational quantum number J equals zero (J = 0). The vibrational level G(υ), inertial rotation constant Bυ and centrifugal distortion constant Dυ are determined when J = 0. All the results of vibrational states except for P16O (X2Π) are reported for the first time. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
9.
Pnictides α‐Ba5P4 and KBa4P5 were prepared by melting the elements. The α‐Ba5P4 compound crystallizes in the orthorhombic system (Sm5Ge4‐type), space group Pnma, Z = 4, a = 8.330(3), b = 16.503(3), c = 8.405(2)Å, it contains two anionic species : P24— dumbbells and P3—. The KBa4P5 compound crystallizes in the tetragonal system, space group P43212, Z = 4, a = 8.559(1), c = 16.102(2)Å, it contains trimers P35— and dumbbells P24—. The crystal structures were solved from single crystal X‐ray data and refined by full‐matrix least‐squares to agreement factors R1 = 0.047 and 0.038, respectively. Using ionic charges, α‐Ba5P4 is formulated as [5Ba2+, 2P3—, P24—] and KBa4P5 as [K+, 4Ba2+, P24—, P35—]. The level of oligomerisation in these structures depends upon the overall valence electron content, bonding within the anionic oligomers has been analyzed on the basis of EHMO calculations and compared to classical or hypervalent bonding in other phosphide compounds. 相似文献
10.
P. K. Mukherjee A. K. Bhattacharya A. Mukherji 《International journal of quantum chemistry》1971,5(6):647-655
A variation perturbation method in the Hartree–Fock scheme has been described to calculate excited 3P state wave functions of atoms. The starting wave functions are obtained from a study of the singularities in the dynamic polarizability calculation [1]. The 23P, 33P and 43P states of He, Li+, Be2+, B3+ and C4+ are studied. The results obtained are in satisfactory agreement with experimental values and with other accurate theoretical estimates. 相似文献
11.
The Flory theory of solution thermodynamics is used to predict exess volumes for systems containing a series of n-alkanes mixed with liquids of higher P* parameter and internal pressure, i.e., cyclopentane, cyclohexane, carbon tetrachloride, benzene and dioxane as well as of lower P*, i.e., decamethyltetrasiloxane. Trends of V
E
, e.g. changes of sign with alkane carbon number are well predicted and indicate the importance of the P* contribution in V
E
. Mixtures of hexane isomers with liquids of much higher P* typically have large excess enthalpies through zero as an S-shaped curve against composition which is negative on the side of the high P* component. This behaviour is interpreted as arising from increasingly large negative P* contributions in V
E
. 相似文献
12.
《Chemical physics》1987,115(2):269-277
Effective electronic polarization energies for positive P+eff and negative P−eff charge carriers in polyacene crystals have been reevaluated. By comparing the P+eff and P−eff values obtained from the analyses of reported energy parameters with calculated data, it is shown that the widely accepted assumption that P+eff = P−eff in polyacene crystals is not valid. By applying recently reported data on optical EoptG and adiabatic EadG energy gap values, the contribution of molecular (vibronic) polarization in the total effective polarization energies W+eff and W−eff has been estimated, and modified energy diagrams for polyacene crystals have been presented. Further, due to practically constant values of observed and calculated P+eff and P−eff in polyacenes, the gap energies between positive and negative charge carrier conduction levels have been estimated for several related aromatic hydrocarbons. 相似文献
13.
《Chemical physics letters》1987,141(4):301-305
Detection of Te atoms in the ground 3P2,1,0 states has been accomplished using two-photon laser-induced fluorescence (LIF) and “2 + 1” multiphoton ionization (MPI). Te atoms were produced by multiphoton dissociation of (C2H5)2Te in the region 358–395 nm. The LIF and MPI experiments utilize selective excitation of the 6p 3PJ′←5p 3PJ″ and 7p 3PJ′←5p 3P2 transitions by two-photon absorption. Line strength intensities for the individual J′ ← J″ fine structure pairs of the 6p 3PJ′ ← 5p 3PJ″ two-photon transitions were calculated and compared to the LIF data. Intensities of these transitions of Te atoms are compared to analogous 3P ← 3P transitions in S and O atoms. 相似文献
14.
Avijit Ghosh Prof. Mangalampalli Ravikanth 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(20):6386-6396
The synthesis, spectroscopic, and electrochemical properties of seven new PV–meso‐triarylcorroles ( 1 – 7 ) are reported. Compounds 1 – 7 were prepared by heating the corresponding free‐base corroles with POCl3 at reflux in pyridine. Hexacoordinate PV complexes of meso‐triarylcorroles were isolated that contained two axial hydroxy groups, unlike the PV complex of 8,12‐diethyl‐2,3,7,13,17,18‐hexamethylcorrole, which was pentacoordinate, or the PV complex of meso‐tetraphenylporphyrin, which was hexacoordinate with two axial chloro groups. 1H and 31P NMR spectroscopy in CDCl3 indicated that the hexacoordinated PV–meso‐triarylcorroles were prone to axial‐ligand dissociation to form pentacoordinated PV–meso‐triarylcorroles. However, in the presence of strongly coordinating solvents, such as CH3OH, THF, and DMSO, the PV–meso‐triarylcorroles preferred to exist in a hexacoordinated geometry in which the corresponding solvent molecules acted as axial ligands. X‐ray diffraction of two complexes confirmed the hexacoordination environment for PV–meso‐triarylcorroles. Their absorption spectra in two coordinating solvents revealed that PV–meso‐triarylcorroles showed a strong band at about 600 nm together with other bands, in contrast to PV–porphyrins, which showed weak bands in the visible region. These compounds were easier to oxidize and more difficult to reduce compared to PV–porphyrins. These compounds were brightly fluorescent, unlike the weakly fluorescent PV–porphyrins, and the quantum yields for selected PV–corroles were as high as AlIII and GaIII corroles, which are the best known fluorescent compounds among oligopyrrolic macrocycles. 相似文献
15.
Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes XXI The Influence of the PR3 Ligands on Formation and Properties of the Phosphinophosphinidene Complexes [{η2‐tBu2P–P}Pt(PR3)2] and [{η2‐tBu2P1–P2}Pt(P3R3)(P4R′3)] (R3P)2PtCl2 and C2H4 yield the compounds [{η2‐C2H4}Pt(PR3)2] (PR3 = PMe3, PEt3, PPhEt2, PPh2Et, PPh2Me, PPh2iPr, PPh2tBu and P(p‐Tol)3); which react with tBu2P–P=PMetBu2 to give the phosphinophosphinidene complexes [{η2‐tBu2P–P}Pt(PMe3)2], [{η2‐tBu2P–P}Pt(PEt3)2], [{η2‐tBu2P–P}Pt(PPhEt2)2], [{η2‐tBu2P–P}Pt(PPh2Et)2], [{η2‐tBu2P–P}Pt(PPh2Me)2], [{η2‐tBu2P–P}Pt(PPh2iPr], [{η2‐tBu2P–P}Pt(PPh2tBu)2] and [{η2‐tBu2P–P}Pt(P(p‐Tol)3)2]. [{η2‐tBu2P–P}Pt(PPh3)2] reacts with PMe3 and PEt3 as well as with tBu2PMe, PiPr3 and P(c‐Hex)3 by substituting one PPh3 ligand to give [{η2‐tBu2P1–P2}Pt(P3Me3)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3Ph3)(P4Me3)], [{η2‐tBu2P1–P2}Pt(P3Et3)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3MetBu2)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3iPr3)(P4Ph3)] and [{η2‐tBu2P1–P2}Pt(P3(c‐Hex)3)(P4Ph3)]. With tBu2PMe, [{η2‐tBu2P–P}Pt(P(p‐Tol)3)2] forms [{η2‐tBu2P1–P2}Pt(P3MetBu2)(P4(p‐Tol)3)]. The NMR data of the compounds are given and discussed with respect to the influence of the PR3 ligands. 相似文献
16.
The line spectra of emitted resonance radiation from mercury and the effective decay rates of the Hg 63P1 and 61P1 levels in mercury–argon discharges are simulated by a Monte Carlo method. The hyperfine splitting, the natural isotopic composition, collisional transfer of excitation, foreign gas collisions and quenching are considered to describe in detail the 253.7 nm and 184.9 nm lines. The calculations are performed for Hg vapor densities corresponding to coldest spot temperatures of 5–100°C, and discharge parameters typical for fluorescent lamp operation. The densities of the Hg 63P1 and 61P1 levels are consistently estimated by means of a set of balance equations for the Hg 63P0, 63P1, 63P2, and 61P1 excited states. The resulting uv radiation output of the discharge is then estimated for a tube radius of 18 mm, argon pressure of 400 Pa, discharge current 0.4 A, and wall temperatures of 20–80°C. The results obtained show a good agreement as compared with published experimental data. 相似文献
17.
Ion-associated halochromates (halo=F, Cl, Br) from tetraphenylphosphonium cation (Ph4P+) are synthesized by stepwise solvent extraction technique and characterized based on XRD, spectral and thermal studies. The
Ph4P+CrO3Br- crystal is tetragonal with a=b=12.368 and c=7.511 ∮A. Thermal stabilities of these complexes are found to be decreasing in
the order of Ph4P+CrO3F-> Ph4P+CrO3Cl-> Ph4P+CrO3Br-.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
Pulsed laser excitation of pyrene (P)/N, N-diethylaniline (DEA) solutions in methanol at low temperatures leads to the generation of the P? and DEA+ radical ions. A fast initial decay of the ions (τ ≈ 37 nsec at ?40°C) is observed and is attributed to geminate recombination within the initially formed (2P?…2DEA+) ion pair. The quenching of 1P*) by DEA is also associated with substantial intersystem crossing, yielding 3P*. The data rule out both gemiate and non-geminate (homogeneous) inonic recombinations as sources for the initial yield of 3P*, in keeping with a prompt triplet formation mechanism. 相似文献
19.
J. Lorenzen H. Hotop M. -W. Ruf 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1986,1(3):261-268
Using crossed beams of alkali atoms (Li, Na, K) and state-selected metastable Ne(3s 3 P 2,3 P 0) atoms, we have measured the energy spectra of electrons resulting in the respective Penning ionization processes at thermal collision energies. The spectra are very different for Ne(3 P 2) and Ne(3 P 0): those for Ne(3 P 2) are broad due to a strongly attractive interaction potential with a well depth of 798 (30) meV (Li), 672(20) meV (Na), and 561(20) meV (K), those for Ne(3 P 0) are narrow and compatible with van der Waals type attraction (well depth <50 meV). The Ne(3 P 2) cross section exceeds the one for Ne(3 P 0) by about an order of magnitude. 相似文献
20.
《Angewandte Chemie (International ed. in English)》2017,56(6):1671-1675
A synthetic approach to the sandwich complex [Cp′′′Co(η4‐P4)] ( 2 ) containing a cyclo‐P4 ligand as an end‐deck was developed. Complex 2 is the missing homologue in the series of first‐row cyclo‐Pn sandwich complexes, and shows a unique tendency to dimerize in solution to form two isomeric P8 complexes [(Cp′′′Co)2(μ,η4:η2:η1‐P8)] ( 3 and 4 ). Reactivity studies indicate that 2 and 3 react with further [Cp′′′Co] fragments to give [(Cp′′′Co)2(μ,η2:η2‐P2)2] ( 5 ) and [(Cp′′′Co)3P8] ( 6 ), respectively. Furthermore, complexes 2 , 3 , and 4 thermally decompose forming 5 , 6 , and the P12 complex [(Cp′′′Co)3P12] ( 7 ). DFT calculations on the P4 activation process suggest a η3‐P4 Co complex as the key intermediate in the synthesis of 2 as well as in the formation of larger polyphosphorus complexes via a unique oligomerization pathway. 相似文献