Relativistic effects determined using the Douglas-Kroll contracted basis sets and correlation consistent basis sets with small-core relativistic pseudopotentials J. Chem. Phys. 122, 174310 (2005); 10.1063/1.1888571Third-order Douglas-Kroll relativistic coupled-cluster theory through connected single, double, triple, and quadruple substitutions: Applications to diatomic and triatomic hydrides Accurate relativistic Gaussian basis sets determined by the third-order Douglas-Kroll approximation with a finitenucleus model Parallel Douglas-Kroll energy and gradients in NWChem: Estimating scalar relativistic effects using Douglas-Kroll contracted basis sets Highly accurate relativistic Gaussian basis sets are developed for the 103 elements from H (Zϭ1) to Lr (Zϭ103). Orbital exponents are optimized by minimizing the atomic self-consistent field ͑SCF͒ energy with the scalar relativistic third-order Douglas-Kroll approximation. The basis sets are designed to have equal quality and to be appropriate for the incorporation of relativistic effects. The basis set performance is tested by calculations on prototypical molecules, hydrides, and dimers of copper, silver, and gold using SCF, Møller-Plesset theory, and the singles and doubles coupled-cluster methods with and without perturbative triples ͓CCSD, CCSD͑T͔͒. Spectroscopic constants and dissociation energies are reported for the ground state of each species. The effects of relativity, electron correlation, and the basis set superposition error ͑BSSE͒ are investigated. At the BSSE corrected CCSD͑T͒ level, the mean absolute error relative to experiment in D e for three dimers ͑hydrides͒ is 0.13 ͑0.09͒ eV; for R e the error is 0.024 ͑0.003͒ Å, and for e it is 2 ͑13͒ cm Ϫ1 . These illustrative calculations confirm that the present basis sets fulfill their design objectives.
Anaplastic large cell lymphoma (ALCL) is a subtype of non-Hodgkin's lymphoma characterized by the CD30+ large neoplastic cells and sometimes carries a t(2;5)(p23;q35). Recently, we found a novel hyperphosphorylated 80-kD protein tyrosine kinase, p80, in ALCLs with t(2;5). Subsequent cDNA cloning showed p80 to be a fusion protein of two genes, the novel tyrosine kinase gene and the nucleophosmin gene, in accordance with the sequence of the NPM/ALK gene (Morris et al, Science 263:1281, 1994). Meanwhile, the clinicopathologic features of p80-carrying ALCLs have remained unclear. Paraffin sections of 105 cases of ALCL were immunostained using anti-p80 antibody, and 30 of them were shown to express p80. Clinicopathologic comparison between p80-positive and -negative ALCLs showed that p80-positive cases occurred in a far younger patient age group (16.2 +/- 12.9 years; p80- negative cases, 51.0 +/- 22.3 years; P < .0001) and the patients showed a far better 5-year survival rate (79.8%; p80-negative group, 32.9%; P < .01). These data showed that p80-positive ALCL is a distinct entity both clinically and pathogenetically and should be differentiated from p80-negative ALCL.
An accurate determination of the effective electric field (E eff ) in YbF is important, as it can be combined with the results of future experiments to give an improved new limit for the electric dipole moment of the electron. We report a relativistic coupled-cluster calculation of this quantity in which all the core electrons were excited. It surpasses the approximations made in the previous reported calculations. We obtain a value of 23.1 GV/cm for E eff in YbF with an estimated error of less than 10%. The crucial roles of the basis sets and the core excitations in our work are discussed.The electric dipole moment (EDM) of a nondegenerate system arises from violations of both the parity (P) and the time-reversal (T) symmetries [1]. T violation implies charge parity (CP) violation via CPT theorem [2]. In general, CP violation is a necessary condition for the existence of the EDMs of physical systems, and, in particular, atoms and molecules. Paramagnetic atoms and molecules are sensitive to the EDM of the electron (eEDM) [3], which is an important probe of the physics beyond the standard model [4]. The eEDM arising from CP violation could also be related to the matter-antimatter asymmetry in the universe [5]. A number of studies using atoms have been performed during the past few decades to extract an upper limit for the eEDM [6]. In general, for heavy polar molecules, the effective electric field experienced by an electron (E eff ) obtained from relativistic molecular calculations can be several orders of magnitude larger than that in atoms [7]. Therefore, the experimental observable (i.e., the shift in energy because of the interaction of the electric field with the eEDM) is also several orders of magnitude larger. Owing to the high sensitivity of the eEDM in molecules, there has been a considerable increase in interest in this field during the past decade The aim of the present work is to calculate E eff in YbF using a rigorous relativistic many-body method, which is more accurate than the methods used in the previous calculations. The method we have chosen is the four-component relativistic coupled-cluster (RCC) method, which is arguably the current gold standard for calculating the electronic structure of heavy atoms and diatomic molecules [18].The electron EDM interaction Hamiltonian in a molecule can be written as [19] Here, d e is the eEDM of an electron, is one of the Dirac matrices, and are the Pauli spin matrices. i is the index of summation labelling for electrons and N e is the total number of electrons. E int is the electric field acting on an electron in a molecule. The quantity that is of experimental interest in the search for the eEDM is an energy shift (E) of a particular state owing to the interaction Hamiltonian given in Eq.(1). This can be expressed as
In this paper we propose to utilize the X 2 g (ν,N,F,M) = (0,0,1/2, ±1/2) → (1,0,1/2, ±1/2) or (2,0,1/2, ±1/2) transition of N 2 + (I = 0) to test variations of the proton-to-electron mass ratio. The X 2 g ground state exhibits no quadrupole shift and the Zeeman shift of the N = 0 → N = 0 transition is exactly zero. Because N 2 + is nonpolar, systematic level shifts such as Stark shifts induced by trap electric field or blackbody radiation are very small and the thermalization of the rotational states is inhibited. This eases the requirements on the experimental setup significantly. Employing Raman transitions at the "magic" wavelength the (0,0,1/2, ±1/2) → (1,0,1/2, ±1/2) or (2,0,1/2, ±1/2) transition frequency can be measured very precisely.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.