Photoassociation spectroscopy of ultracold Cs below the 6P1/2 limit

We have performed high precision photoassociation spectroscopy of ultracold cesium gas. Using trap-loss fluorescence detection and controlling the background cesium pressure we were able to photoassociate atoms into excited states of ultracold molecules with large detunings up to 56 cm(-1) below the Cs(6S(1/2)) + Cs(6P(1/2)) atomic asymptote. Vibrational progressions are assigned to 0(g)(-), 0(u)(+), and 1(g) long-range states. By fitting the spectral data to the LeRoy-Bernstein expression, the effective coefficients of the leading long-range interactions and the vibrational quantum number at dissociation are obtained. In addition we have observed spectral perturbations between states of the same symmetry belonging to different asymptotes (6P(1/2) and 6P(3/2)). The perturbations are manifested through irregular vibrational level spacings and are especially pronounced in the 0(u)(+) symmetry. Many observed rotational levels indicate d- and higher partial wave contributions to the photoassociation cross section in the presence of trapping laser light, while spectral regions with only weak features suggest nodes in the lower state wave functions corresponding to the two ground state atoms asymptote.     

Photoassociation studies of ultracold NaCs from the Cs 6(2)P(3/2) asymptote

A combination of pulsed depletion spectroscopy and photoassociation spectroscopy is utilized to assign photoassociation spectra of NaCs. These methods investigate the ab initio Ω = 2 potential energy curve and indicate a previously unknown avoided crossing between the (3)Ω = 1 and (4)Ω = 1 electronic states. We present rotational assignments of deeply bound singlet ground state molecules, an improved C(6) coefficient for the (4)Ω = 1 and assignments for all twenty-three photoassociation resonances detuned from the Cs 6(2)P(3/2) asymptote.     

Photoassociation spectroscopy of ultracold metastable 3He dimers

The bound states of the fermionic (3)He(2 (3)S(1)) + (3)He(2 (3)P(j)) system, where j = 0, 1, 2, are investigated using the recently available ab initio short-range (1,3,5)Σ(+)(g,u) and (1,3,5)Π(g,u) potentials computed by Deguilhem et al. (J. Phys. B: At., Mol. Opt. Phys., 2009, 42, 015102). Single-channel and multichannel calculations have been undertaken in order to investigate the effects of Coriolis and non-adiabatic couplings. The possible experimental observability of the theoretical levels is assessed using criteria based upon the short-range character of each level and their coupling to metastable ground states. Purely long-range levels have been identified and 30 short-range levels near five asymptotes are suggested for experimental investigation.     

NaMn6(P2O7)2(P3O10) and KCd6(P2O7)2(P3O10)

The crystal structures of two new diphosphates, sodium hexamanganese bis­(diphosphate) triphosphate, NaMn₆(P₂O₇)₂(P₃O₁₀), and potassium hexacadmium bis­(diphosphate) triphosphate, KCd₆(P₂O₇)₂(P₃O₁₀), confirm the rigidity of the M₆(P₂O₇)₂(P₃O₁₀) matrix (M is Mn or Cd) and the relatively fixed dimensions of the tunnels extending in the a direction of the unit cell. The compounds are isomorphous; the P₂O₇^4? anion and the alkali metal cations lie on mirror planes. Bond‐valence analysis of the bonding details of the atoms found within the tunnels permits a prediction of the conductivity.     

The triple pyrophosphate Cs3CaFe(P2O7)2

The complex phosphate tricaesium calcium iron bis(diphosphate), Cs₃CaFe(P₂O₇)₂, has been prepared by the flux method. Isolated [FeO₅] and [CaO₆] polyhedra are linked by two types of P₂O₇ groups into a three‐dimensional framework. The latter is penetrated by hexagonal channels along the a axis where three Cs atoms are located. Calculations of caesium Voronoi–Dirichlet polyhedra give coordination schemes for the three Cs atoms as [8 + 3], [9 + 1] and [9 + 4]. The structure includes features of both two‐ and three‐dimensional frameworks of caesium double pyrophosphates.     

Die ungewöhnliche Umwandlung von P(SnMe3)3 in P4(SnMe2)6

The Unusual Transformation of P(SnMe₃)₃ to P₄(SnMe₂)₆ The stannylated phosphine P(SnMe₃)₃ reacts in the presence of small amounts of [(ZnCl)₂Fe(CO)₄(THF)₂] in THF (tetrahydrofurane) at room temperature forming insoluble P₄(SnMe₂)₆ ( 1 ). This compound crystallizes as colourless needles directly from the reaction mixture (space group Cmcm, a = 1593.6(3) pm, b = 1118.2(2), c = 1602.5(3), Z = 4). Reaction of ZnCl₂ with P(SnMe₃)₃ under the same reaction conditions leads to the complex [ZnCl₂{P(SnMe₃)₃}THF] ( 2 ) (space group Pccn, a = 1593, 6(3) pm, b = 1118, 2(2), c = 1602, 5(3), Z = 8.     

Über Hexafluoroferrate(III): Cs2TlFeF6, Cs2KFeF6, Rb2KFeF6, Rb2NaFeF6 und Cs2NaFeF6

On Hexafluoroferrates(III): Cs₂TlFeF₆, Cs₂KFeF₆, Rb₂KFeF₆, Rb₂NaFeF₆, and Cs₂NaFeF₆ New prepared are the compounds Cs₂TlFeF₆ (a = 9.21₁ Å), Cs₂KFeF₆ (a = 9.04₁ Å), Rb₂KFeF₆ (a = 8.86₈ Å) and Rb₂NaFeF₆ (a = 8.46 ₄Å) all cubic Elpasolithes as well as Cs₂NaFeF₆ (Cs₂NaCrF₆?type, hexagonal with a = 6.28₁, c = 30.53₂ Å), all colourless. Cs₂KFeF₆ was measured magnetically (70–297,2 K). The spectra of reflection were measured (9000–36000 cm^?1). The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Identification of a new family of phosphate compounds,AIBII6(P2O7)2P3O10: structures of KMn6(P2O7)2P3O10 and AgMn6(P2O7)2P3O10

Two members of a new family of inorganic phosphates of general formula A^IB^II₆(P₂O₇)₂P₃O₁₀; KMn₆(P₂O₇)₂P₃O₁₀ (a=5.405(2), b=26.918(11), c=6.660(5), β=107.31(3)°, V=925.1(9) Å³, space group P2₁/m, Z=2, D_calc=3.481 Mg m⁻³, R=0.0377 for 2235 observed reflections) and AgMn₆(P₂O₇)₂P₃O₁₀ (a=5.424(7), b=26.97(4), c=6.627(9), β=106.81(7)°, V=928(2) Å³, space group P2₁/m, Z=2, D_calc=3.716 Mg m⁻³, R=0.0594 for 1577 observed reflections) have been synthesized and identified by single crystal X-ray diffraction. The isostructural complexes present an interesting comparison of silver and potassium bonding.     

Synthese und Struktur eines Caesium-tetraimidophosphat-diamids,Cs5[P(NH)4](NH2)2 = Cs3[P(NH)4] · 2 CsNH2

Synthesis and Crystal Structure of a Cesium-tetraimidophosphate-diamide, Cs₅[P(NH)₄](NH₂)₂ = Cs₃[P(NH)₄] · 2 CsNH₂ Well crystallized Cesium-tetraimidophosphate-diamide is obtained by the reaction of CsNH₂ with P₃N₅ in autoclaves at 673 K within three days. X-ray single crystal investigations led to the following data

• Ccca, Z = 4, a = 8.192(5) Å, b = 20.472(5) Å,
• c = 8.252(3) Å
• Z(F) ≥3σ(F) = 916, Z(Var.) = 32, R/R_w=1 = 0.017/0.021

The compound contains the hitherto unknown anion [P(NH)₄]^3?.     

Quenching of I(2P1/2) by O3 and O(3P)

Oxygen-iodine lasers that utilize electrical or microwave discharges to produce singlet oxygen are currently being developed. The discharge generators differ from conventional chemical singlet oxygen generators in that they produce significant amounts of atomic oxygen. Post-discharge chemistry includes channels that lead to the formation of ozone. Consequently, removal of I(2P1/2) by O atoms and O3 may impact the efficiency of discharge driven iodine lasers. In the present study, we have measured the rate constants for quenching of I(2P1/2) by O(3P) atoms and O3 using pulsed laser photolysis techniques. The rate constant for quenching by O3, (1.8 +/- 0.4) x 10(-12) cm3 s-1, was found to be a factor of 5 smaller than the literature value. The rate constant for quenching by O(3P) was (1.2 +/- 0.2) x 10(-11) cm3 s-1.     

Alkali Metal Hexaphosphenes(4) as Sources for the Polycyclic Compounds P7R3, Cs3P11 and Cs4P14

Abstract

The alkalimetal hexaphosphenes(4) M₄P₆(M=K,Rb,Cs) are built up in the solid state by cations M⁺ and a monocyclic six membered planar ring P₆ ^4? /1,2/. Reactions with RCl (R=SnMe₃) in glyme at ?70°C led to the well known heptaphosphanortri-cyclenes P₇R₃ (a), and with P₄ in en to the undecaphosphide anion P₁₁ ^3? in form of the solvated crystalline Cs compound (b) as well as to a quadrodecapnosphide (c) P₁₄ ^4?, known already from a sodium compound.     

Thermoelectric properties of quaternary Uranium chalcogenides Cs2Pt3US6 and Cs2Pt3USe6

Electronic and thermoelectric behaviors of Cs₂Pt₃US₆ and Cs₂Pt₃USe₆ compounds have been revealed in the present work. The calculations have been performed with the help of full potential linearized augmented plane wave method (FP-LAPW). Engel–Vosko generalize gradient approximation was used for the exchange correlation energy. Thermoelectric properties were deal with generalized BoltzTraP program. Band structure calculation resulted in metallic nature of the materials. Calculated Fermi surfaces have been found to consist of two sheets. Bonding characteristics have studied with the help of electron charge density in (1 1 0) crystallographic plane. Seebeck coefficient, electric conductivity, power factor, figure of merit and thermal conductivity has been calculated.     

Excitation energy transfer in the Li-Cs collision: Li*(2P)+Cs(6S)→Li(2S)+Cs*(5D)

The measurement of the collisional cross section for the process Li*(2P)+Cs(6S)→Li(2S)+Cs*(5D) are reported. The technique of resonant Doppler-limited two-photon laser excitation with thermionic detection is applied. The population density of the Cs*5D state is probed by photoionization, and the signals of the Cs(6S)→Cs*(5D) and the Li(2S)→Li*(2P) transitions are compared. The value for cross section of 30 Ų is measured, with an accuracy of 45%.     

Catalytic activity and visible spectroscopy of [Rh(norbornadiene)Cl]2/p-RC6H4)3P system in methanol

Summary The catalytic hydrogenation of hex-1-ene in methanolic solution with [Rh(norbornadiene)Cl]₂/(p-RC₆H₄)₃ P (R=H, Me or OMe) systems preparedin situ has been measured. The catalytic activity shows a dependence on the ageing of the catalyst precursor solution in the presence of air. A spectroscopic study (visible region) has been carried out for the system with triphenyl phosphine and shows degradation with the formation of [Rh(norbornadiene)PPh₃Cl] as an intermediate. It was demonstrated that the spectral changes and the consequent catalytic activity are due to PPh₃ loss because of the oxygen dissolved in the media.     

Caesium vanadium selenite,Cs(VO2)3(SeO3)2

Caesium vanadium(V) selenite contains infinite sheets of distorted vertex‐sharing VO₆ octahedra, capped by selenite groups [d_av(V—O) = 1.927 (4) Å and d_av(Se—O) = 1.709 (3) Å]. Interlayer caesium cations complete the structure [d_av(Cs—O) = 3.365 (4) Å].     

Kristallstruktur von Hexamincyclotriphosphazen,P3N3(NH2)6

Crystal Structure of Hexamine Cyclotriphosphazene, P₃N₃(NH₂)₆ In the presence of KNH₂ hexamine cyclotriphosphazene semi ammoniate (molar ratio 12:1) in NH₃ gives crystals of solvent free P₃N₃(NH₂)₆ within 5 d at 130°C and p(NH₃) = 110 bar. The structure was solved by X-rax methods: P₃N₃(NH₂)₆: P2₁/c, Z = 4, a = 10.889(6) Å, b = 5.9531(6) Å, c = 13.744(8) Å, β = 97.83(3)°, Z(F_o) = 1 721 with (F_o)² ≥ 3σ(F_o)², Z(var.) = 157, R/R_w = 0,036/0,041 The structure contains columns of molecules P₃N₃(NH₂)₆ all in the same orientation. The six-membered rings within one molecule have boat conformation. The columns are stacked together in a way that one is surrounded by four others shifted by half a lattice constant in direction [010]. Strong hydrogen bridge-bonds N? H…?N connect molecules within the columns and between them.