Zobrazeno 1 - 10
of 208
pro vyhledávání: '"Kvaal, Simen"'
We introduce a simple definition of the weight of any given Slater determinant in the coupled-cluster state, namely as the expectation value of the projection operator onto that determinant. The definition can be applied to any coupled-cluster formul
Externí odkaz:
http://arxiv.org/abs/2411.00690
Real-time propagation methods for chemistry and physics are invariably formulated using variational techniques. The time-dependent bivariational principle (TD-BIVP) is known to be the proper framework for coupled-cluster type methods, and is here stu
Externí odkaz:
http://arxiv.org/abs/2410.24192
Recent advances in attosecond science have made it increasingly important to develop stable, reliable and accurate algorithms and methods to model the time evolution of atoms and molecules in intense laser fields. A key process in attosecond science
Externí odkaz:
http://arxiv.org/abs/2404.07699
The assumptions underpinning the adiabatic Born-Oppenheimer (BO) approximation are broken for molecules interacting with attosecond laser pulses, which generate complicated coupled electronic-nuclear wavepackets that generally will have components of
Externí odkaz:
http://arxiv.org/abs/2401.11926
Autor:
Ofstad, Benedicte Sverdrup, Wibowo-Teale, Meilani, Kristiansen, Håkon Emil, Aurbakken, Einar, Kitsaras, Marios Petros, Schøyen, Øyvind Sigmundson, Hauge, Eirill, Kvaal, Simen, Stopkowicz, Stella, Wibowo-Teale, Andrew M., Pedersen, Thomas Bondo
We present a numerical approach to magnetic optical rotation based on real-time time-dependent electronic-structure theory. Not relying on perturbation expansions in the magnetic-field strength, the formulation allows us to test the range of validity
Externí odkaz:
http://arxiv.org/abs/2308.06003
Autor:
Aurbakken, Einar, Ofstad, Benedicte Sverdrup, Kristiansen, Håkon Emil, Schøyen, Øyvind Sigmundson, Kvaal, Simen, Sørensen, Lasse Kragh, Lindh, Roland, Pedersen, Thomas Bondo
Based on the work done by an electromagnetic field on an atomic or molecular electronic system, a general gauge invariant formulation of transient absorption spectroscopy is presented within the semi-classical approximation. Avoiding multipole expans
Externí odkaz:
http://arxiv.org/abs/2307.02519
Autor:
Ofstad, Benedicte Sverdrup, Kristiansen, Håkon Emil, Aurbakken, Einar, Schøyen, Øyvind Sigmundson, Kvaal, Simen, Pedersen, Thomas Bondo
Real-time simulations of laser-driven electron dynamics contain information about molecular optical properties through all orders in response theory. These properties can be extracted by assuming convergence of the power series expansion of induced e
Externí odkaz:
http://arxiv.org/abs/2302.02779
Autor:
Faulstich, Fabian M., Kristiansen, Håkon E., Csirik, Mihaly A., Kvaal, Simen, Pedersen, Thomas Bondo, Laestadius, Andre
We propose a novel a posteriori error assessment for the single-reference coupled-cluster (SRCC) method called the $S$-diagnostic. We provide a derivation of the $S$-diagnostic that is rooted in the mathematical analysis of different SRCC variants. W
Externí odkaz:
http://arxiv.org/abs/2301.11393
Autor:
Schrader, Simon Elias, Kvaal, Simen
The coupled cluster method is considered a gold standard in quantum chemistry, reliably giving energies that are exact within chemical accuracy (1.6 mHartree). However, even in the CCSD approximation, where the cluster operator is truncated to includ
Externí odkaz:
http://arxiv.org/abs/2212.07928
Autor:
Kvaal, Simen
Moreau-Yosida regularization is introduced into the framework of exact DFT. Moreau-Yosida regularization is a lossless operation on lower semicontinuous proper convex functions over separable Hilbert spaces, and when applied to the universal function
Externí odkaz:
http://arxiv.org/abs/2208.05268