Staggering effects in nuclear and molecular spectra
D. Bonatsos, N. Karoussos, C. Daskaloyannis, S. B. Drenska, N. Minkov, P. P. Raychev, R. P. Roussev, J. Maruani
备注：
LaTeX, 16 pages plus 30 figures given in separate .ps files. To appear in the proceedings of the 4th European Workshop on Quantum Systems in Chemistry and Physics (Marly-le-Roi, France, 1999), ed. J. Maruani et al. (Kluwer, Dordrecht)
发表信息：
Prog. Theor. Chem. Phys. 6 : New Trends in Quantum Systems in Chemistry and Physics, ed. J. Maruani, C. Minot, R. McWeeny, Y. G. Smeyers, and S. Wilson, Vol. I (Kluwer, Dordrecht, 2001) p. 393.
It is shown that the recently observed Delta J = 2 staggering effect (i.e. the relative displacement of the levels with angular momenta J, J+4, J+8, ..., relatively to the levels with angular momenta J+2, J+6, J+10, ...) seen in superdeformed nuclear bands is also occurring in certain electronically excited rotational bands of diatomic molecules (YD, CrD, CrH, CoH), in which it is attributed to interband interactions (bandcrossings). In addition, the Delta J = 1 staggering effect (i.e. the relative displacement of the levels with even angular momentum J with respect to the levels of the same band with odd J) is studied in molecular bands free from Delta J = 2 staggering (i.e. free from interband interactions/bandcrossings). Bands of YD offer evidence for the absence of any Delta J = 1 staggering effect due to the disparity of nuclear masses, while bands of sextet electronic states of CrD demonstrate that Delta J = 1 staggering is a sensitive probe of deviations from rotational behaviour, due in this particular case to the spin-rotation and spin-spin interactions.
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Nuclear quantum effects are important in a variety of chemical and biological processes. The constrained nuclear-electronic orbital density functional theory (cNEO-DFT) has been developed to include nuclear quantum effects in energy surfaces. Herein we develop the analytic Hessian for cNEO-DFT energy with respect to the change of nuclear (expectation) positions, which can be used to characterize stationary points on energy surfaces and compute molecular vibrational frequencies. This is achieved by constructing and solving the multicomponent cNEO coupled-perturbed Kohn-Sham (cNEO-CPKS) equation…
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The energies of molecular excited states arise as solutions to the electronic Schrödinger equation and are often compared to experiment. At the same time, nuclear quantum motion is known to be important and to induce a red-shift of excited state energies. However, it is thus far unclear whether incorporating nuclear quantum motion in molecular excited state calculations leads to a systematic improvement of their predictive accuracy, making further investigation necessary. Here we present such an investigation by employing two first-principles methods for capturing the effect of quantum fluctua…
We introduce a pseudo-mass parameterized Schrödinger-like alchemical equation which contains nuclear charges as variables, treating nuclear charges, nuclear coordinates and electronic coordinates on the equal footing. The eigenfunctions of the alchemical equation are the wave functions of nuclear charges, just like conventional wave functions are of coordinates. A mathematical definition of alchemical function space is given to hold the ''nuclear charge wave function''. The geometric phase of alchemical dynamics and alchemical phase space are also derived. For hydrogen-like ion, the alchemical…
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Production of Spin-Polarized Molecular Beams via Microwave or Infrared Rotational Excitation
Institut für Laser- und Plasmaphysik, Heinrich-Heine-Universität Düsseldorf（杜塞尔多夫海因里希·海涅大学激光与等离子体物理研究所）；Department of Physics, University of Crete（克里特大学物理系）；Institute of Electronic Structure and Lasers, Foundation for Research and Technology-Hellas（希腊基础研究与技术基金会电子结构与激光研究所）
As an extension of two-level quantum bits (qubits), multilevel systems, so-called qudits, where d represents the Hilbert space dimension, have been predicted to reduce the number of iterations in quantum computation algorithms. This has been tested in the well-known [TbPc2]0 SMM, which allowed the implementation of the Grover algorithm in a single molecular unit. In the quest for molecular systems possessing an increased number of accessible nuclear spin states, we explore herein a dimeric Tb2-SMM via single crystal μ-SQUID measurements at sub-Kelvin temperatures. We observe ferromagnetic inte…
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Motivated by recent synthetic and theoretical progress we consider magnetism in crystals of multi-nuclear organometallic complexes. We calculate the Heisenberg symmetric exchange and the Dzyaloshinskii-Moriya antisymmetric exchange. We show how, in the absence of spin-orbit coupling, the interplay of electronic correlations and quantum interference leads to a quasi-one dimensional effective spin model in a typical tri-nuclear complex, Mo$_3$S$_7$(dmit)$_3$, despite its underlying three dimensional band structure. We show that both intra- and inter-molecular spin-orbit coupling can cause an eff…
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The Born-Oppenheimer electronic wavefunction $Φ_R^{BO}(r)$ picks up a topological phase factor $\pm 1$, a special case of Berry phase, when it is transported around a conical intersection of two adiabatic potential energy surfaces in $R$-space. We show that this topological quantity reverts to a geometric quantity $e^{iγ}$ if the geometric phase $γ= \oint \mathrm{Im} \langle Φ_R |\nabla_μ Φ_R\rangle \cdot d\mathbf{R}_μ$ is evaluated with the conditional electronic wavefunction $Φ_R(r)$ from the exact electron-nuclear factorization $Φ_R(r)χ(R)$ instead of the adiabatic function $Φ_R^{BO}(r)$. A…
