Results 121 to 130 of about 130,152 (295)

Linear and Two‐Dimensional Infrared Spectroscopy of the Multifunctional Vibrational Probe, 3‐(4‐Azidophenyl) Propiolonitrile. Deperturbing a Fermi Triad by Isotopic Substitution

ChemPhysChem, Volume 26, Issue 6, March 15, 2025.
Linear infrared spectroscopy combined with isotope labeling and density functional theory unravels the origin of a Fermi triad in a multifunctional vibrational chromophore. Ultrafast 2DIR‐spectroscopy reports directly on the dynamics and the intramolecular vibrational energy flow pathways in the isotopically deperturbed system. Abstract Infrared probes
Claudia Gräve, Jörg Lindner, Stefan Flesch, Luis I. Domenianni, Peter Vöhringer   +4 more
wiley   +1 more source

Pairs of positive solutions for resonant singular equations with the p-Laplacian

Electronic Journal of Differential Equations, 2017
We consider a nonlinear elliptic equation driven by the Dirichlet p-Laplacian with a singular term and a (p-1)-linear perturbation which is resonant at $+\infty$ with respect to the principal eigenvalue. Using variational tools, together with suitable
Nikolaos S. Papageorgiou, Vicentiu D. Radulescu, Dusan D. Repovs   +2 more
doaj  

Graph-theoretical approach to the eigenvalue spectrum of perturbed higher-order exceptional points

Physical Review Research
Exceptional points are special degeneracy points in parameter space that can arise in (effective) non-Hermitian Hamiltonians describing open quantum and wave systems.
Daniel Grom, Julius Kullig, Malte Röntgen, Jan Wiersig   +3 more
doaj   +1 more source

Conservation of the Total Order of the Axial SiSi and N → Si Bonds in Oligosilanylsilatranes

ChemPhysChem, EarlyView.
Total bond order (the sum of inversely related bSiSi and bN → Si bond orders) in oligo‐silanylsilatranes is constant and equal to unity unequivocally proving 3c‐4e character of the N → SiSi bond and a distinct covalent contribution in the N → Si interaction.
Elena F. Belogolova, Evgeniya P. Doronina, Judith Baumgartner, Christoph Marschner, Viatcheslav V. Jouikov   +4 more
wiley   +1 more source

Perturbation nonlinearly dependent on the eigenvalue and a condensation of perturbation theory

Journal of Mathematical Analysis and Applications, 1969
where H,, is a self-adjoint operator with known spectral measure E. for the complex Hilbert space X and G, is given as a symmetric operator in X depending on h, and where by a solution pair u, h to (1.1) we mean that X is to be a real scalar and u is to be a nonnull X vector belonging to both the domain of H,, and of G, and (1.1) is to be satisfied by ...
openaire   +3 more sources

AGORA: Adaptive Generation of Orthogonal Rational Approximations for Frequency‐Response Data

International Journal of Circuit Theory and Applications, EarlyView.
This paper introduces the adaptive generation of orthogonal rational approximations (AGORA) method for rational function approximation of measured or simulated microwave network parameters. AGORA allows estimating the model order for a given error tolerance and does not require any initial estimates or adjustment of hyperparameters. ABSTRACT This paper
Andria Lemus, Arif Ege Engin
wiley   +1 more source

Subcritical perturbations of resonant linear problems with sign-changing potential

Electronic Journal of Differential Equations, 2005
We establish existence and multiplicity theorems for a Dirichlet boundary-value problem at resonance. This problem is a nonlinear subcritical perturbation of a linear eigenvalue problem studied by Cuesta, and includes a sign-changing potential. We obtain
Teodora-Liliana Dinu
doaj  

Perturbation theory of multiparameter eigenvalue problems

Journal of Mathematical Analysis and Applications, 1988
Let \(T_ r\) and \(V_{rs}\) be linear selfadjoint operators in Hilbert spaces \({\mathfrak H}_ r\). Let \(\lambda_ s\) be complex parameters. Then it is considered the multiparameter system \[ (T_ r+\sum^{k}_{s=1}\lambda_ sV_{rs})u_ r=0,\quad r=1,...,k. \] The main objective is to study the influence of perturbations for the operators \(T_ r\).
openaire   +3 more sources

Untangling sedimentation processes in a deep fjord lake in Labrador: A high‐resolution archive of past environment dynamics at Grand Lake

The Depositional Record, EarlyView.
Sedimentological and geochemical characteristics are used to reconstruct sedimentation dynamics and erosional processes. Several rapidly deposited layers are characterised over changing depositional environments during the Late Holocene, from a phase when the lake was connected to the sea to a more stable state conducive to varve formation.
Milena S. Kury, Pierre Francus, Léo Chassiot, Dermot Antoniades, Guillaume St‐Onge, Juliette Girard, Patrick Lajeunesse   +6 more
wiley   +1 more source

Perturbation and interlace theorems for the unitary eigenvalue problem [PDF]

, 1993
L. Elsner, Chunyang He
openalex   +1 more source