Search results for "Intersection"

On the FCNS⇆FC(NS) reaction: A matrix isolation and theoretical study

2015

Abstract The FCNS ⇆ FC(NS) photoisomerization process is a simple model system for molecular switches. Here, we examined the switching processes by experimental and theoretical methods. Prior matrix-isolation IR spectroscopic studies were complemented by matrix-isolation UV spectroscopic measurements to assist the interpretation of the mechanism of the ring closure and opening processes and to verify the accuracy of the computations on the vertical excitation energies. Vertical excitation energies were computed by the EOMEE-CCSD, MCSCF, and MR-CISD methods. Conical intersections were also searched for and three conical intersections along the reaction path FCNS → FC(NS) were located, one co…

ApproximatingL 2-invariants by their finite-dimensional analogues

1994

LetX be a finite connectedCW-complex. Suppose that its fundamental group π is residually finite, i.e. there is a nested sequence ... ⊂ Г m + 1 ⊂ Г m ⊂ ... ⊂ π of in π normal subgroups of finite index whose intersection is trivial. Then we show that thep-thL 2-Betti number ofX is the limit of the sequenceb p(Xm)/[π:Г m ] whereb p(Xm) is the (ordinary)p-th Betti number of the finite covering ofX associated with Г m .

Existentially closed locally cofinite groups

1992

Let be a class of finite groups. Then a c-group shall be a topological group which has a fundamental system of open neighbourhoods of the identity consisting of normal subgroups with -factor groups and trivial intersection. In this note we study groups which are existentially closed (e.c.) with respect to the class Lc of all direct limits of c-groups (where satisfies certain closure properties). We show that the so-called locally closed normal subgroups of an e.c. Lc-group are totally ordered via inclusion. Moreover it turns out that every ∀2-sentence, which is true for countable e.c. L-groups, also holds for e.c. Lc-groups. This allows it to transfer many known properties from e.c. L-group…

Gendered Labor Market (dis)advantages in Nordic Welfare States. Introduction to the Theme of the Special Issue

2021

Gender equality has been named as one of the normative foundations of Nordic wel- fare states. This is reflected in how, year after year, Nordic states rank among the most gender egalitarian countries in the world (see, e.g., World Economic Forum 2020). In Nordic countries, the state has been, and continues to be, a central actor in shaping women’s citizenship, labor market opportunities, and caring roles. Especially publicly funded welfare services and policies that facilitate the reconciliation of work and care have played a major part in advancing women’s labor market participation (see, e.g., Bergquist et al. 1999; Borchorst & Siim 2002; Ellingsæter & Leira 2006; Siim & Stol…

Effects of the Binding Communication Paradigm on Attitudes

2012

International audience; The binding communication approach is situated at the intersection of research on persuasive communication and commitment. Binding communication refers to the combination of a preparatory act involving commitment and a persuasive message. Two studies showed that differences in attitudes toward recycling (Study 1) or swimming (Study 2) are more likely to occur following a persuasive message combined with a preparatory act involving commitment (i.e., binding communication) as compared to either technique alone. Specifically, in Study 1 we observed a more favorable attitude toward recycling in the binding communication condition compared to the conditions involving only…

Toward an Understanding of Ultrafast Electron Transfer in Photosynthesis

2008

The mechanism of electron transfer (ET) from reduced pheophytin (Pheo−) to the primary stable photosynthetic acceptor, a quinone (Q) molecule, is addressed by using high-level ab initio computations and realistic molecular models. The results reveal that the ET process involving the (Pheo−+Q) and (Pheo+Q−) oxidation states can be seen essentially as an ultrafast radiationless transition between the two hypersurfaces taking place via conical intersections (CIs) and is favoured when the topology of the interacting moieties makes possible some overlap between the lowest occupied molecular orbitals (LUMO) of the two systems. Thus, it is anticipated that large scale motions, which are difficult …

2014

There have been a number of recent experimental investigations of the nonadiabatic relaxation dynamics of aniline following excitation to the first three singlet excited states, 1(1)ππ*, 1(1)π3s/πσ* and 2(1)ππ*. Motivated by differences between the interpretations of experimental observations, we have employed CASSCF and XMCQDPT2 calculations to explore the potential energy landscape and relaxation pathways of photoexcited aniline. We find a new prefulvene-like MECI connecting the 1(1)ππ* state with the GS in which the carbon-atom carrying the amino group is distorted out-of-plane. This suggests that excitation above the 1(1)π3s/πσ* vertical excitation energy could be followed by electronic…

Can coupled-cluster theory treat conical intersections?

2007

Conical intersections between electronic states are of great importance for the understanding of radiationless ultrafast relaxation processes. In particular, accidental degeneracies of hypersurfaces, i.e., between states of the same symmetry, become increasingly relevant for larger molecular systems. Coupled-cluster theory, including both single and multireference based schemes, offers a size-extensive description of the electronic wave function, but it sacrifices the Hermitian character of the theory. In this contribution, we examine the consequences of anti-Hermitian contributions to the coupling matrix element between near-degenerate states such as linear dependent eigenvectors and compl…

Geometrically enhanced closed-loop multi-turn sensor devices that enable reliable magnetic domain wall motion

2017

We experimentally realize a sophisticated structure geometry for reliable magnetic domain wall-based multi-turn-counting sensor devices, which we term closed-loop devices that can sense millions of turns. The concept relies on the reliable propagation of domain walls through a cross-shaped intersection of magnetic conduits, allowing for the intertwining of loops of the sensor device. As a key step to reach the necessary reliability of the operation, we develop a combination of tilted wires called the syphon structure at the entrances of the cross. We measure the control and reliability of the domain wall propagation individually for cross-shaped intersections, the syphon geometries, and fin…

Similar chemical structures, dissimilar triplet quantum yields: a CASPT2 model rationalizing the trend of triplet quantum yields in nitroaromatic sys…

2019

The photophysics of nitroaromatics compounds stand out for being characterized by an ultrafast decay into the triplet manifold and by a significant value of the triplet quantum yield. The latter quantity can change dramatically from one system to another, as proven for the molecules 2- nitronaphthalene, 1-nitronaphthalene, and 2methyl-1nitronaphthale, whose triplet quantum yield have been previously measured to be 0.93 ± 0.15, 0.64 ± 0.12, and 0.33 ± 0.05, respectively (J. Phys. Chem. A 2013, 117, 14100). In the present contribution we rationalize the reported trend for the triplet quantum yield on the basis of the different ability that the excited S 1 state has in the three molecules to r…