Research Explorer

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Researcher

Helen van Aggelen

Awards & Distinctions

33 Results

2014

Assessing the quality of new quantum chemical methods by comparison with Full CI exchange-correlation holes

Guillaume AckeHelen van AggelenPaul W AyersDimitri Van NeckPatrick BultinckCarlos Cardenas

Exchange-correlation energy from pairing matrix fluctuation and the particle-particle random phase approximation

Helen van AggelenYang YangWeitao Yang

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

Linear-response time-dependent density-functional theory with pairing fields

Degao PengHelen van AggelenYang YangWeitao Yang

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

2013

Assessing the quality of new quantum chemical methods by comparison with Full CI exchange-correlation holes

Guillaume AckeHelen van AggelenPaul W AyersPatrick BultinckCarlos Cardenas

Benchmark tests and spin adaptation for the particle-particle random phase approximation

Yang YangHelen van AggelenStephan N SteinmannDegao PengWeitao Yang

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

Double, Rydberg and charge transfer excitations from pairing matrix fluctuation and particle-particle random phase approximation

Yang YangHelen van AggelenWeitao Yang

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

Equivalence of particle-particle random phase approximation correlation energy and ladder-coupled-cluster doubles

Degao PengStephan N SteinmannHelen van AggelenWeitao Yang

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

Exchange-correlation energy from pairing matrix fluctuation and the particle-particle random-phase approximation

Helen van AggelenYang YangWeitao Yang

A1 Journal Article in PHYSICAL REVIEW A

Extended random phase approximation method for atomic excitation energies from correlated and variationally optimized second-order density matrices

Helen van AggelenBrecht VerstichelGuillaume AckeMatthias DegrootePatrick BultinckPaul W AyersDimitri Van Neck

A1 Journal Article in COMPUTATIONAL AND THEORETICAL CHEMISTRY

Extensive v2DM study of the one-dimensional Hubbard model for large lattice sizes : exploiting translational invariance and parity

Brecht VerstichelHelen van AggelenWard PoelmansSebastian WoutersDimitri Van Neck

A1 Journal Article in COMPUTATIONAL AND THEORETICAL CHEMISTRY

The sharp-G N-representability condition

Paul A JohnsonPaul W AyersBrecht VerstichelDimitri Van NeckHelen van Aggelen

A1 Journal Article in COMPUTATIONAL AND THEORETICAL CHEMISTRY

The tensor hypercontracted parametric reduced density matrix algorithm: coupled-cluster accuracy with O(r⁴) scaling

Neil ShenviHelen van AggelenYang YangWeitao YangChristine SchwerdtfegerDavid Mazziotti

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

2012

Considerations on describing non-singlet spin states in variational second order density matrix methods

Helen van AggelenBrecht VerstichelPatrick BultinckDimitri Van NeckPaul W Ayers

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

Variational density study of the one-dimensional Hubbard model : the need for three-particle constraints

Brecht VerstichelHelen van AggelenWard PoelmansDimitri Van Neck

Variational optimization of second order density matrices: the past, the present and the future

Helen van AggelenBrecht VerstichelPatrick BultinckDimitri Van NeckPaul W Ayers

Variational two-particle density matrix calculation for the Hubbard model below half filling using spin-adapted lifting conditions

Brecht VerstichelHelen van AggelenWard PoelmansDimitri Van Neck

A1 Journal Article in PHYSICAL REVIEW LETTERS

2011

A primal-dual semidefinite programming algorithm tailored to the variational determination of the two-body density matrix

Brecht VerstichelHelen van AggelenDimitri Van NeckPatrick BultinckStijn De Baerdemacker

A1 Journal Article in COMPUTER PHYSICS COMMUNICATIONS

Nonstandard N-representability constraints and their application to chemical and physical systems

Dimitri Van NeckBrecht VerstichelHelen van AggelenPatrick BultinckPaul W Ayers

Variational density matrix optimization using semidefinite programming

Brecht VerstichelHelen van AggelenDimitri Van NeckPaul W AyersPatrick Bultinck

A1 Journal Article in COMPUTER PHYSICS COMMUNICATIONS

Variational optimization of second order density matrices for electronic structure calculation

Helen van AggelenPatrick BultinckDimitri Van Neck

Variational second order density matrix study of F3- : importance of subspace constraints for size-consistency

Helen van AggelenBrecht VerstichelPatrick BultinckDimitri Van NeckPaul W AyersDavid L Cooper

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

2010

Chemical verification of variational second-order density matrix based potential energy surfaces for the N-2 isoelectronic series

Helen van AggelenBrecht VerstichelPatrick BultinckDimitri Van NeckPaul W AyersDavid L Cooper

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

Chemical verification of variationally optimized second order density matrices

Helen van AggelenBrecht VerstichelPatrick BultinckDimitri Van NeckPaul W AyersDavid L Cooper

Subsystem constraints in variational second order density matrix optimization : curing the dissociative behavior

Brecht VerstichelHelen van AggelenDimitri Van NeckPaul W AyersPatrick Bultinck

A1 Journal Article in JOURNAL OF CHEMICAL PHYSICS

2009

Chemical implications of variational second-order density matrix theory : study of diatomic molecules along the potential energy curve

Helen van AggelenBrecht VerstichelPaul W. AyersPatrick BultinckDavid L. CooperDimitri Van Neck

Dissociation curves from variational second order density matrices : an Atoms in Molecules perspective

Patrick BultinckHelen van AggelenBrecht VerstichelDimitri Van NeckPaul W. Ayers

Incorrect diatomic dissociation in variational reduced density matrix theory arises from the flawed description of fractionally charged atoms

Helen van AggelenPatrick BultinckBrecht VerstichelDimitri Van NeckPaul W. Ayers

A1 Journal Article in PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Variational determination of the second-order density matrix

Brecht VerstichelHelen van AggelenDimitri Van NeckPaul W. AyersPatrick Bultinck

Variational determination of the second-order density matrix for the isoelectronic series of beryllium, neon, and silicon

Brecht VerstichelHelen van AggelenDimitri Van NeckPaul W AyersPatrick Bultinck

A1 Journal Article in PHYSICAL REVIEW A

Variational optimization of the second-order density matrix: application to molecular dissociation

Helen van AggelenBrecht VerstichelPatrick BultinckDimitri Van NeckPaul W. Ayers

Variational optimizaton of the second order density matrix apllied to the dissociation of diatomic molecules

Helen van AggelenPatrick BultinckDimitri Van NeckBrecht VerstichelPaul W Ayers

Variational reduced density matrix theory : successes and failures

Paul W AyersDimitri Van NeckPatrick BultinckHelen van AggelenBrecht Verstichel

2008

STUDY OF THE DISSOCIATION OF DIATOMIC MOLECULES BY MEANS OF THE CORRELATED DELOCALIZATION INDEX

Helen van AggelenD. Van NeckPatrick Bultinck