Use of a new cluster ansatz to treat strong relaxation and correlation effects: a direct method for energy differences

We have presented in this paper a new cluster Ansatz for the wave operator for open-shell and/or quasidegenerate states, which takes care of strong relaxation and correlation effects in a compact and efficient manner. This Ansatz allows contraction among the various cluster operators via spectator orbitals, accompanied by suitable combinatorial factors. Since both the orbital and the correlation relaxations are treated on the same footing, it allows us to develop a very useful direct method for energy differences for open shell states relative to a closed-shell ground state, where the total charge for the two states may differ. We have discussed a new spin-free coupled cluster (CC) based direct method and illustrated its performance by evaluating electron affinity of a neutral doublet radical. We have also indicated how the scope of the theory can be extended to compute the state energies of simple open shell configurations as well. In that case, the CC equations terminate after the quartic power of cluster operators - exactly as in the closed-shell situation, which is not the case for the current methods

Unsteady CFD Studies for Gust Modeling in Store Separation

Aircraft and different store configurations must be certified before a flight. There is a small but finite probability of aircraft being hit by gust wind at the time of separation. Most store separation analyses from airborne platforms do not consider the gust phenomena because of the complexity and inadequate knowledge of its behavior. A dedicated task group was recently created to understand the gust-related phenomena in aircraft safety. Of the various gust cases, vertical gust is most severe and can cause instability leading to store collision. The situation is compounded in a long and heavy store due to its large projected area. No test procedures exist for simulation or practical tests of gust. A study was conducted to identify a test procedure for gust simulation using MIL standard data and Indian conditions. The current paper studies the emergency release condition where a vertical gust is hitting the aircraft to ascertain safe separation. A discrete gust with a 1-cosine shape and specified length and amplitude is imposed at the inflow boundary. The gust is allowed to sweep the computational domain containing the airborne platform and the store. The computed trajectory of the store, the miss distance, and its angular rates in the presence of gust are analysed in this work to study the safe separation of a store from an airborne platform. Simulations are also carried out to determine the effect of gust at the highest dynamic pressure in the flight envelope

Carboxylato bridging Cu(II) coordination polymer: Structure, magnetism and catalytic reduction of nitrophenols

The 1D coordination polymer, [Cu 2 ( μ2 -OH) 2 (DABA) 2 ] n ( 1 ), (HDABA = 4-Diallylamino-benzoic acid) is characterized by Single crystal X-Ray diffraction analysis. The structure switches to a 2D geometry by hy- drogen bonding interactions. Hand grinding aqueous suspension of the coordination polymer, 1 , present in nano regime of av . 100 nm dimension and shows catalytic performance in the reduction of toxic nitro- phenols to corresponding aminophenols by NaBH 4 . The rate constant values ( κapp ) are 2.4 ×10 −3 (4-NP), 5.3 ×10 −3 (2,4-DNP) and 5.6 ×10 −3 (2,4,6-TNP) s −1 are much higher than reduction by only NaBH 4 . The susceptibility measurements ( χM T ) of Cu(II) coordination polymer indicates the presence of a very weak antiferromagnetic coupling between the metal centres. The hand grinding technique and reusability of 1 makes the approach chemically green, cost effective and attracts the attention towards the real-life application

DDC-wise subject mapping of NDLI indexed multileveled, multilingual resources: A special reference with Indian Languages

The study helped with the subject mapping of the resources on 22 languages included in the Indian constitution that were indexed in the National Digital Library of India from 2018 and covering the different fields of arts and humanities, social sciences, science, engineering, technology, and history. The subject mapping is based on the Dewey Decimal Classification (DDC) 22nd edition. The relevant/required data was collected from the official website of the National Digital Library of India (https://ndl.iitkgp.ac.in/) on 4th April 2021, Sunday by browsing subject-wise. (https://ndl.iitkgp.ac.in/result?q={ t : subject , b :{ browse : subject , filters :[]}}) and filtering one by one of 22 officially recognized Indian languages in the Indian constitution. A total number of 398793 documents on different subjects indexed in NDLI till 4th April 2021, The maximum number of documents indexed in Computer science, Information & general works (000) subject [88.98%] and the larger number of documents indexed in the Bengali language [40.71%]

Modified Born-Lande Equation to calculate Lattice Energy in a theoretical approach

Defects in ionic solid are very much common, which is increased with the rise in temperature. It causes the change in the value of many physical properties and varieties of physical parameters and the Lattice Energy is one such parameter to control the physical properties of the crystals. Considering the loss of ions from lattice points as random, the examination of each of the defects individually is going to be unpredictable, thus leading to almost nonattainment of the correct crystal structure with the theoretical calculations applying for available models. Here, in this present work, we have used some statistical methods and probabilistic approximation to introduce a novel idea of calculating the Madelung constant, and then Lattice Energy analytically. To make the understanding more lucid, we have taken one of the very common crystals, very popular in the crystallographic community, NaCl crystal having 6:6 co-ordination number, for which a significant number of Schottky defects are observed. During this study, we are bound to assume the random distribution of defects as Poisson distribution due to the fact that the number of defects is very less with respect to the total numbers of lattice points present in the crystal to calculate the Madelung Constant

THERAPEUTIC MANAGEMENT OF BOVINE CUTANEOUS PAPILLOMATOSIS WITH IVERMECTIN IN FARM BRED CALF CROPS OF WEST BENGAL, INDIA

Incidence of infectious bovine cutaneous papillomatosis in farm bred calf crops of tropical West Bengal during 2008-2010 and its successful therapeutic management with injectable Ivermectin is reported. Diagnosis was based on clinicopathology and histopathological findings and effects of parenteral Ivermectin were clinically evaluated in 36 calves where Ivermectin was administered @ 1ml/50 kg body wt. by subcutaneous route for 3 occassions at 15 days interval. Hundred percent clinical recovery (n = 36) was observed in treatment group whereas persistence as well as different stages of papillomatous growth without regression or self cure was observed in (n = 10) control group

A novel VU-MRCC formalism for the simultaneous treatment of strong relaxation and correlation effects with applications to electron affinity of neutral radicals

We present and implement in this paper a novel spin-free valence-universal multi-reference coupled cluster (VU-MRCC) formalism for energy differences which can capture orbital relaxation and correlation relaxation to all orders. Unlike in the traditional normal ordered cluster Ansatz for computing energy differences, this cluster expansion formalism allows contractions between various valence excitation operators with valence spectator lines. These contractions simulate the orbital relaxation and correlation relaxation effects for the ionized/excited states via Thouless-like exponential type of operators. Generally such operators are non-commuting. To ensure that each distinct excitation generated by contracted composites formed by these operators appear only once in the wave-operators, the factors accompanying these composites have to be judiciously chosen. Hence, the combinatoric factors accompanying such contracted composites are not taken to be 1/n! for nth-power, but rather the inverse of the automorphic factor (the number of ways the n operators can be connected in various permutations generating the same composite). It is shown that this Ansatz leads to a set of VU-MRCC equations for the valence cluster amplitudes, in which all the cluster operators are attached to the hamiltonian by at least one non-spectator line (a strongly connected series). The series is thus terminating at the quartic power. Illustrative applications are presented by computing electron affinity of neutral doublet radicals (viz., NH2, OH, F, BO and CN), where the orbital relaxation effect attendant on the anion formation is considerable. Several basis-sets capable of describing the anions have been studied. It has been found that aug-cc-pVTZ basis gives the best overall results, while aug-cc-pVQZ overestimates the electron affinity, presumably because of an imbalance in describing the neutral radicals. The method performs consistently much better then the one with the traditional normal ordered Ansatz

Development and applications of a relaxation-inducing cluster expansion theory for treating strong relaxation and differential correlation effects

We present in this paper a multi-reference coupled cluster (MRCC) formulation for energy differences which treats orbital relaxation and correlation effects on the same footing, by invoking a novel cluster ansatz of the valence portion of the wave operator Ωv. Unlike in the traditional normal-ordered exponential representation of Ωv, our new relaxation-inducing ansatz, represented symbolically as E r(S), allows contractions between the spectator lines and also certain other special contractions. By an extensive theoretical analysis, taking as an example the case of one-hole model space (the IP problem), we demonstrate that our ansatz incorporates in a manifestly spin-free form the orbital relaxation to all orders. The traditional Thouless-type of exponential transformation via one-body excitations can induce the same effect, as is done in the valence-specific or the quasi-valence-specific MRCC formalisms, but they have to be done in the spin-orbital basis - making the spin adaptation of the problem a complicated exercise. In contrast, we use a spin-free representation of the cluster operators right from start, but expand the rank of the cluster operators by involving spectator orbitals to distinguish the various spin possibilities. The combinatorial factors entering the contracted power series in E r(S) are chosen in such a way that they correspond to what we would have obtained if we had used a Thouless-like transformation to induce the orbital relaxation. Our working equations generally have only finite powers of the cluster operators S, resulting in a very compact formulation of the relaxation problem. Pilot numerical applications for the IP computations of HF and H2O in the core, the inner valence and the outer valence regions show very good performance of the method vis-a-vis those obtained using the traditional normal ordered ansatz for Ωv. The improvement in the core IP value is particularly impressive, although even for the valence regions there is an overall improvement of the IP values