A New Approach To Relativistic Gaussian Basis Functions: Theory And Applications

We present a new hybrid method to solve the relativistic Hartree-Fock-Roothan equations where the one- and two-electron radial integrals are evaluated numerically by defining the basis functions on a grid. This procedure reduces the computational costs in the evaluation of two-electron radial integrals. The orbitals generated by this method are employed to compute the ionization potentials, excitation energies and oscillator strengths of alkali-metal atoms and elements of group IIIA through second order many-body perturbation theor and other correlated theories.Comment: RevTex (15 pages) one figur

Micellar effects upon the reactions of complex ions in solution. Part 4. Kinetics of aquation and base hydrolysis of some cis-(chloro)(amine)bis(ethylenediamine)cobalt(III) complexes in the presence of neutral and anionic surfactants in an aqueous medium

The binding of the substrates cis-[Co(en)2BCl]2+(en = 1,2-diaminoethane, B = alkylamines, imidazole, N-methylimidazole) to the micellar surface of sodium dodecyl sulphate resulted in the retardation of their dissociative aquation rates, the effect being sensitive to the hydrophobicity of the nonlabile amine ligand B. A contrastingly small rate acceleration for the corresponding ethanolamine and propan-2-ol amine complexes was observed under similar conditions. Triton X-100 (0.02 ≤ [Triton X]T/mol dm-3 ≤ 0.1) had virtually no effect on the aquation rates of such complexes except for cis-[Co(en)2(C6H11NH2)Cl]2+, in which case a small rate retardation was also observed. The rates of base hydrolysis of the cobalt(III) substrates were strongly retarded by the anionic micelles of SDS; the neutral micelles of Triton X-100 were effective in decelerating the rate of base hydrolysis of the cyclohexylamine complex cis-[Co(en)2(C6H11NH2)Cl]2+ only. The pseudo-phase ion-exchange equilibrium model satisfactorily explained the binding of the cationic substrates to the anionic micellar pseudo-phase of SDS. The values of the ion-exchange equilibrium constant and the relative base hydrolysis rates (kW/kM) indicated that both micellar binding and retardation of hydrolysis are governed by hydrophobic and electrostatic interactions

Decarboxylation of Hydrogencarbonatopentamminecobalt(III) in Aquo-organic solvent media

The decarboxylation of hydrogencarbonatopentaamminecobalt(III) has been investigated in aqueous, 99% D2O and aquo-organic solvent media (0-70 wt.% of cosolvent) at 15 ≤ t/°C ≤ 40 (I = 0.02 mol dm-3), using methanol, propan-2-01, tert-butyl alcohol, ethylene glycol, acetone, acetonitrile, DMSO and ethylene carbonate as cosolvents. The solvent isotope effects on rate (kH2O/kD2O=O 1.0 at 1535°C) and activation parameters (ΔH≠ = 77.7 ± 1.0, 77.8 ± 0.9 kJ mol-1 and ΔS≠ = 16 ± 3, 16 ± 3 J K-1 mol-1 for aqueous and 99% D,O media, respectively) were negligible. The decarboxylation rate constant increased with increasing mole fraction (Xorg) of the cosolvent and the effect was pronounced at relatively high values of Xorg for the dipolar aprotic cosolvents. This was attributed to a greater degree of destabilisation of the initial state as compared to the transition state with increasing mole fraction of the cosolvent. The In ks vs. 1/εs plots (ks is the rate constant and εs, the bulk relative permittivity) showed marked dependence on the nature of the cosolvents; the gradients of such plots generally increased with increasing dipole moment of the cosolvent molecules, indicating thereby that the solvation of the initial state and the transition state of the substrate is governed by the ion-dipole interactions between the water and cosolvent molecules. The relative transfer free energy of activation, [ΔΔGt≠](s←w), decreased linearly with Xorg for all mixed-solvent media, indicating that the preferential solvation effect is not significant. The activation enthalpy and entropy vs. Xorg plots displayed extrema suggesting that these thermodynamic parameters are sensitive to the structural changes in the bulk solvent phase. The solvent effects on ΔH≠ and ΔS≠ are mutually compensatory

Relativistic coupled-cluster-based linear response theory for ionization potentials of alkali-metal and alkaline-earth-metal atoms

We have developed and applied the relativistic coupled-cluster-based linear response theory (RCCLRT) for computing the principal as well as the shake-up ionization potentials (IP's) of Li, Be, Na, and Mg where the single-particle orbitals are generated by solving the relativistic Hartree-Fock-Roothaan equations using the Gaussian basis functions on a grid. The computed principal and shake-up ionization energies by the RCCLRT approach are in favorable agreement with the experimental results. Since for the (one-valence) IP problem, there is a formal equivalence between the principal IP values as obtained from the CCLRT and those obtained as eigenvalues of the multireference coupled-cluster theory, the computed quantities are fully size extensive. The approach via the RCCLRT has the additional advantage of providing the shake-up IP's as well. These are, however, not fully size extensive, but the error scales as the number of valence excitations (2h-1p), so the inextensivity error is rather small

Clinicopathological study of soft tissue sarcoma-retrospective study of tertiary cancer institute in eastern India

Background: Soft tissue sarcomas are a rare and heterogeneous group of malignant tumors of mesenchymal origin that comprise less than 1 percent of all adult malignancies. Although they occur anywhere in the body, they involve most commonly in extremities, trunk, retroperitoneum and head and neck. The aim of the study was to analyze clinical and histopathological features of various soft tissue sarcomas.Methods: This was a retrospective study, conducted in tertiary cancer centre in Odisha during the period 2015 to 2018. We collected clinical parameters like age, sex, site of swelling, any associated pain and biopsy reports and these variables were correlated with final histopathology reports.Results: A total of 107 patients were included in the study, with male to female ratio of 2:1(71 and 36) and average age of 43.45 years. All of them presented with a swelling. The lower extremities were the most common sites i.e. 44.62%. Pleomorphic sarcoma was the most frequent histologic variety comprising 43% and less frequent variety were angiosarcoma, and myxoid sarcoma.Conclusions: Soft tissue sarcoma are predominant in males and middle aged population are frequently affected. Most common affected site is lower extremity and pleomorphic sarcoma is the prominent histologic type

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

Observation of tW production in the single-lepton channel in pp collisions at root s=13 TeV

A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at root s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb(-1) collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant t (t) over bar background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 +/- 4 (stat) +/- 12 (syst) pb, consistent with the standard model.Peer reviewe

Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at root s=5.02 TeV Using Leptonic Decays

The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb(-1). Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as sigma(WW) = 37:0(-5.2)(+5.5) (stat)(-2.6)(+2.7) (syst) pb, sigma(WZ) = 6.4(-2.1)(+2.5) (stat)(-0.3)(+0.5)(syst) pb, and sigma(ZZ) = 5.3(-2.1)(+2.5)(stat)(-0.4)(+0.5) (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy