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21.
Filsinger F Meijer G Stapelfeldt H Chapman HN Küpper J 《Physical chemistry chemical physics : PCCP》2011,13(6):2076-2087
The manipulation of the motion of neutral molecules with electric or magnetic fields has seen tremendous progress over the last decade. Recently, these techniques have been extended to the manipulation of large and complex molecules. In this article we introduce experimental approaches to the manipulation of large molecules, i.e., the deflection, focusing and deceleration using electric fields. We detail how these methods can be exploited to spatially separate quantum states and how to select individual conformers of complex molecules. We briefly describe mixed-field orientation experiments made possible by the quantum-state selection. Moreover, we provide an outlook on ultrafast diffraction experiments using these highly controlled samples. 相似文献
22.
Hansen JL Nielsen JH Madsen CB Lindhardt AT Johansson MP Skrydstrup T Madsen LB Stapelfeldt H 《The Journal of chemical physics》2012,136(20):204310
We study how the combination of long and short laser pulses can be used to induce torsion in an axially chiral biphenyl derivative (3,5-difluoro-3',5'-dibromo-4'-cyanobiphenyl). A long, with respect to the molecular rotational periods, elliptically polarized laser pulse produces 3D alignment of the molecules, and a linearly polarized short pulse initiates torsion about the stereogenic axis. The torsional motion is monitored in real-time by measuring the dihedral angle using femtosecond time-resolved Coulomb explosion imaging. Within the first 4 picoseconds (ps), torsion occurs with a period of 1.25 ps and an amplitude of 3° in excellent agreement with theoretical calculations. At larger times, the quantum states of the molecules describing the torsional motion dephase and an almost isotropic distribution of the dihedral angle is measured. We demonstrate an original application of covariance analysis of two-dimensional ion images to reveal strong correlations between specific ejected ionic fragments from Coulomb explosion. This technique strengthens our interpretation of the experimental data. 相似文献
23.
A theoretical concept of local manipulation of magnetic domain walls is introduced. In the proposed procedure, a domain wall is driven by a spin-polarized current induced by a magnetic tip, as used in a scanning tunneling microscope, placed above a magnetic nanostripe and then moved along its long axis with a current flowing through the vacuum barrier. The angular momentum from the spin-polarized current exerts a torque on the magnetic moments underneath the tip and leads to a displacement of the domain wall. Particularly, the manipulation of a ferromagnetic 180° transverse domain wall has been studied by means of Landau-Lifshitz-Gilbert dynamics and Monte Carlo simulations. Different relative orientations of the tip and the sample magnetization have been considered. 相似文献
24.
Hansen JL Stapelfeldt H Dimitrovski D Abu-samha M Martiny CP Madsen LB 《Physical review letters》2011,106(7):073001
A nanosecond laser pulse confines the spatial orientation of naphthalene in 1D or 3D while a femtosecond kick pulse initiates rotation of the molecular plane around the fixed long axis. Time-dependent photoelectron angular distributions (PADs), resulting from ionization by an intense femtosecond probe pulse, exhibit pronounced changes as the molecular plane rotates. Enhanced 3D alignment, occurring shortly after the kick pulse, provides strongly improved contrast in molecular-frame PADs. Calculations in the strong-field approximation show that the striking structures observed in the PADs originate from nodal planes in occupied valence orbitals. 相似文献
25.
Ch. Sannié W. G. Brown H. Flood Ch. Lapp K. Erali H. Brockmann Hella Schodder H. H. Strain P. Ruggli P. Jensen E. Waldschmitt-Leitz P. Fisher-Jørgensen M. Tønnesen G. Schramm J. Primosigh G. -M. Schwab K. Dockers G. Siewert H. Jungnickel Gretl Dattler A. N. Ghosh M. Venturello N. Agliardi H. Dahn H. Erlenmeyer W. Schoenauer und J. N. Wison 《Fresenius' Journal of Analytical Chemistry》1943,126(3):101-117
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26.
Hella Folkerts Bernhard Neumüller Kurt Dehnicke Wolfgang Hiller Martin Herker 《无机化学与普通化学杂志》1995,621(4):531-536
Phosphorane Iminato Complexes of Sulfur. Syntheses and Crystal Structures of [O3SS(NPPh3)2] · CH3CN, [SO(NPPh3)2], and [SCl(NPMe3)2]Cl The title compounds have been prepared by the reaction of Me3SiNPPh3 with SO2 and SOCl2, respectively, and by the reaction of Me3SiNPMe3 with S2Cl2. They form colourless, moisture sensitive crystals, which were characterized by IR spectroscopy and by crystal structure determinations. [O3SS((NPPh3)2)] · CH3CN : Space group Pca21, Z = 4, structure solution with 4016 observed unique reflections, R = 0.050. Lattice dimensions at ?60°C: a = 1865.1, b = 1168.4, c = 1569.0 pm. The compound has a zwitterionic structure with a S? S bond length of 218.2 pm and bond lengths S? N of 161.2 and P? N of 160.1 pm. [SO(NPPh3)2] : Space group P21/c, Z = 4, structure solution with 2854 observed unique reflections, R = 0.113. Lattice dimensions at ?50°C: a = 1173.1, b = 1585.6, c = 1619.2 pm, b? = 98.13°. The compound forms monomeric molecules, in which the positions of S and N atoms are disordered in two positions. The bond lengths are S? N 166 pm and P? N 163 pm in average. [SCl(NPMe3)2]Cl : Space group P1 , Z = 2, structure solution with 2416 observed unique reflections, R = 0.038. Lattice dimensions at 20°C: a = 613.2, b = 1030.3, c = 1111.4 pm, α = 88.48°, b? = 88.01°, γ = 83.10°. The compound forms ions [SCl(NPMe3)2]+ and Cl?. In the cation the sulfur atom is ?-tetrahedrally coordinated with a long S? Cl distance of 246.9 pm and bond lengths S? N of 155.3 pm and P? N of 164.3 pm in average. 相似文献
27.
Hella Folkerts Kurt Dehnicke Ccilia Maichle-Mssmer Joachim Strhle 《无机化学与普通化学杂志》1995,621(7):1171-1174
Synthesis and Crystal Structure of the Selenyl-Phosphoraneiminato Complex SeO(NPPh3)2 SeO(NPPh3)2 has been prepared from SeO2 and Me3SiNPPh3 in a SeO2 suspension in acetonitrile, forming colourless crystals. The compound is characterized by IR spectroscopy and by a crystal structure determination. Space group P1 , Z = 2, structure solution with 5 344 observed unique reflections, R = 0.064. Lattice dimensions at ?40°C: a = 931.6, b = 947.6, c = 1 762 pm, α = 77.50°, β = 81.78°, γ = 79.23°. The compound forms monomeric molecules in which the selenium atom is φ-tetrahedrally surrounded with bond lengths SeO = 161.7 pm and SeN = 179.9 and 181.6 pm. 相似文献
28.
29.
Synthesis and Crystal Structure of a New Modification of Tetraselenium Tetranitride, Se4N4 β-Se4N4 has been prepared by the reaction of selenium dioxide with the phosphane imine Me3SiNPMe3 in acetonitrile, forming red-brown crystal needles. The crystal structure analysis shows a new modification, the IR spectrum of which differs only slightly from the known α-form of Se4N4 (space group C2/c). β-Se4N4: Space group P21/n, Z = 4, structure solution with 1 667 observed unique reflections, R = 0.054. Lattice dimensions at ?50°C: a = 881.8(2), b = 738.7(2), c = 899.6(2) pm, β = 93.58(1)°. Just as the α-form β-Se4N4 forms cage molecules without symmetry and intramolecular Se? Se contacts of 273.2 and 274.0 pm. There are strong Se…?N-interactions between the Se4N4 molecules. 相似文献
30.
Arts Werner Bretschneider Hans-Joachim Buschhoff Hella Rickert Björn 《Analytical and bioanalytical chemistry》1984,319(5):501-505
Analytical and Bioanalytical Chemistry - Die Betriebserfahrungen mit dem Gerät PAR 384A —mit zwei Elektrodenständen PAR 303 —haben gezeigt, daß die Inversvoltammetrie... 相似文献