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First Records, New Species, and a Key of the Charipinae (Hymenoptera: Cynipoidea: Figitidae) from the Nearctic Region
2014
Abstract The Charipinae material deposited in the United States National Museum of Natural History (Smithsonian Institution) and some specimens deposited in the Canadian National Collection of Insects from the Nearctic region have been revised. In all, 337 specimens have been included in this study and 27 species have been determined. Sixteen species are reported for the first time from the Nearctic region: Alloxysta arcuata (Kieffer, 1902), Alloxysta brevis (Thomson, 1862), Alloxysta castanea (Hartig, 1841), Alloxysta citripes (Thomson, 1862), Alloxysta darci (Girault, 1933), Alloxysta fracticornis (Thomson, 1862), Alloxysta halterata (Thomson, 1862), Alloxysta macrophadna (Hartig, 1841), …
Description of new Alloxysta (Hymenoptera: Cynipoidea: Figitidae) species from India
2015
Abstract One new species has been discovered: Alloxysta nottoni Ferrer-Suay & Pujade-Villar sp. nov. This new species is here described and illustrated. An update of the Charipinae knowledge in India and a key of the Charipinae present in this country are also given.
Charipinae fauna from New Zealand with descriptions of two new species ofAlloxystaFörster (Hymenoptera: Cynipoidea: Figitidae: Charipinae)
2012
Biologically, New Zealand is an important country for its high levels of endemism. However, the recorded fauna of Charipinae in this country included only three cosmopolitan species: Alloxysta fuscicornis (Hartig), Alloxysta victrix (Westwood) and Phaenoglyphis villosa (Hartig). Here, we describe the first endemic charipines for New Zealand: Alloxysta rubidus n. sp. and Alloxysta thorpei n. sp. This significantly increases the knowledge of cynipoid diversity in Australasia, where this hymenopteran group is very poorly known. The new species are diagnosed, described, illustrated and information about their hosts and distribution is given. Characters useful to distinguish these species are di…
Review of the Hartig type collection of Alloxysta (Hymenoptera: Figitidae:Charipinae) and other Alloxysta material deposited in the Zoologische Staat…
2014
Hartig's collection of Alloxysta species, deposited in the Zoologische Staatssammlung Museum (ZSM, Munich, Germany), is here reviewed. In total, 19 species and 144 specimens have been studied. Fourteen species, of the previous twenty-two, are now valid: Alloxysta aperta (Hartig, 1841), A. brachyptera (Hartig, 1840), A. castanea (Hartig, 1841), A. circumscripta (Hartig, 1841), A. fuscicornis (Hartig, 1841), A. leunisii (Hartig, 1841), A. longipennis (Hartig, 1841), A. macrophadna (Hartig, 1841), A. melanogaster (Hartig, 1840), A. obscurata (Hartig, 1840), A. pilipennis (Hartig, 1840), A. postica (Hartig, 1841), A. minuta (Hartig, 1840) and A. rufiventris (Hartig, 1840). These species are red…
The chemical bonds in CuH, Cu2, NiH, and Ni2 studied with multiconfigurational second order perturbation theory
1994
The performance of multiconfigurational second order perturbation theory has been analyzed for the description of the bonding in CuH, Cu2, NiH, and Ni2. Large basis sets based on atomic natural orbitals (ANOS) were employed. The effects of enlarging the active space and including the core‐valence correlation contributions have also been analyzed. Spectroscopic constants have been computed for the corresponding ground state. The Ni2 molecule has been found to have a 0+g ground state with a computed dissociation energy of 2.10 eV, exp. 2.09 eV, and a bond distance of 2.23 Å. The dipole moments of NiH and CuH are computed to be 2.34 (exp. 2.4±0.1) and 2.66 D, respectively. pou@uv.es ; merchan@…
Generalized Many-Body Expanded Full Configuration Interaction Theory
2019
Facilitated by a rigorous partitioning of a molecular system's orbital basis into two fundamental subspaces - a reference and an expansion space, both with orbitals of unspecified occupancy - we generalize our recently introduced many-body expanded full configuration interaction (MBE-FCI) method to allow for electron-rich model and molecular systems dominated by both weak and strong correlation to be addressed. By employing minimal or even empty reference spaces, we show through calculations on the one-dimensional Hubbard model with up to 46 lattice sites, the chromium dimer, and the benzene molecule how near-exact results may be obtained in a entirely unbiased manner for chemical and physi…
Many-Body Expanded Full Configuration Interaction. II. Strongly Correlated Regime
2019
In this second part of our series on the recently proposed many-body expanded full configuration interaction (MBE-FCI) method, we introduce the concept of multideterminantal expansion references. Through theoretical arguments and numerical validations, the use of this class of starting points is shown to result in a focussed compression of the MBE decomposition of the FCI energy, thus allowing chemical problems dominated by strong correlation to be addressed by the method. The general applicability and performance enhancements of MBE-FCI are verified for standard stress tests such as the bond dissociations in H$_2$O, N$_2$, C$_2$, and a linear H$_{10}$ chain. Furthermore, the benefits of em…
Virtual Orbital Many-Body Expansions: A Possible Route towards the Full Configuration Interaction Limit
2017
In the present letter, it is demonstrated how full configuration interaction (FCI) results in extended basis sets may be obtained to within sub-kJ/mol accuracy by decomposing the energy in terms of many-body expansions in the virtual orbitals of the molecular system at hand. This extension of the FCI application range lends itself to two unique features of the current approach, namely that the total energy calculation can be performed entirely within considerably reduced orbital subspaces and may be so by means of embarrassingly parallel programming. Facilitated by a rigorous and methodical screening protocol and further aided by expansion points different from the Hartree-Fock solution, al…
Convergence of coupled cluster perturbation theory.
2016
The convergence of a recently proposed coupled cluster (CC) family of perturbation series [Eriksen, J. J. et al., J. Chem. Phys. 140, 064108 (2014)], in which the energetic difference between two CC models - a low-level parent and a high-level target model - is expanded in orders of the M{\o}ller-Plesset (MP) fluctuation potential, is investigated for four prototypical closed-shell systems (Ne, singlet methylene, distorted HF, and the fluoride anion) in standard and augmented basis sets. In these investigations, energy corrections of the various series have been calculated to high orders and their convergence radii determined by probing for possible front- and back-door intruder states, the…
Incremental Treatments of the Full Configuration Interaction Problem
2020
The recent many-body expanded full configuration interaction (MBE-FCI) method is reviewed by critically assessing its advantages and drawbacks in the context of contemporary near-exact electronic structure theory. Besides providing a succinct summary of the history of MBE-FCI to date within a generalized and unified theoretical setting, its finer algorithmic details are discussed alongside our optimized computational implementation of the theory. A selected few of the most recent applications of MBE-FCI are revisited, before we close by outlining its future research directions as well as its place among modern near-exact wave function-based methods.