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51.
Korff BM Troppmann U Kompa KL de Vivie-Riedle R 《The Journal of chemical physics》2005,123(24):244509
Our concept for a quantum computational system is based on qubits encoded in vibrational normal modes of polyatomic molecules. The quantum gates are implemented by shaped femtosecond laser pulses. We adopt this concept to the new species manganese pentacarbonyl bromide [MnBr(CO)5] and show that it is a promising candidate in the mid-infrared (IR) frequency range to connect theory and experiment. As direct reference for the ab initio calculations we evaluated experimentally the absorption bands of MnBr(CO)5 in the mid-IR as well as the related transition dipole moments. The two-dimensional potential-energy surface spanned by the two strongest IR active modes and the dipole vector surfaces are calculated with density-functional theory. The vibrational eigenstates representing the qubit system are determined. Laser pulses are optimized by multitarget optimal control theory to form a set of global quantum gates: NOT, CNOT, Pi, and Hadamard. For all of them simply structured pulses with low pulse energies around 1 microJ could be obtained. Exemplarily for the CNOT gate we investigated the possible transfer to experimental shaping, based on the mask function for pulse shaping in the frequency regime as well as decomposition into a train of subpulses. 相似文献
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Xilei Lin Ch. Lierse von Gostomski 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):1921-1925
The k 0-values were determined for five high Q 0(n,γ) reactions, including 74Se(n,γ) 75Se, 109Ag(n,γ) 110mAg, 114Cd(n,γ) 115Cd–115mIn, 130Ba(n,γ) 131Ba, and 152Sm(n,γ) 153Sm. These determinations were carried out under favorable experiment conditions: the irradiations were performed in a highly thermalized neutron flux, the irradiated target samples were counted at a far distance from HPGe detector with an efficiency carefully calibrated, and the k 0-values were calculated against an internal comparator. When compared to the new values from this work, the 2003 recommended 110mAg k 0-values are confirmed. The other confirmed recommended k 0-value is that of 75Se 400.7 keV line. However, for the other 75Se γ-lines, the new k 0-values are 4–10 % higher. It is assumed that an inaccurate efficiency calibration was used when the recommended k 0-values were measured. For the other three nuclides, the new k 0-values are higher by 4 % for the 115Cd–115mIn γ-lines, lower by 6–8 % for the 131Ba γ-lines, and lower by 8.8 % for the 153Sm 103.2 keV γ-line. 相似文献
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Ana Isabel González Flórez Eike Mucha Dr. Doo‐Sik Ahn Sandy Gewinner Dr. Wieland Schöllkopf Prof. Dr. Kevin Pagel Dr. Gert von Helden 《Angewandte Chemie (International ed. in English)》2016,55(10):3295-3299
Here we present a combined experimental and theoretical study on the secondary structure of isolated proteins as a function of charge state. In infrared spectra of the proteins ubiquitin and cytochrome c, amide I (C=O stretch) and amide II (N–H bend) bands can be found at positions that are typical for condensed‐phase proteins. For high charge states a new band appears, substantially red‐shifted from the amide II band observed at lower charge states. The observations are interpreted in terms of Coulomb‐driven transitions in secondary structures from mostly helical to extended C5‐type hydrogen‐bonded structures. Support for this interpretation comes from simple energy considerations as well as from quantum chemical calculations on model peptides. This transition in secondary structure is most likely universal for isolated proteins that occur in mass spectrometric experiments. 相似文献