01730nas a2200169   4500008004100000022001400041245009200055210006900147260007100216300001400287490000600301520107000307100002701377700001801404700001601422856012201438       2012                        eng d  a1549-961800aNOx catalyzed pathway of stratospheric ozone depletion: a coupled cluster investigation0 aNOx catalyzed pathway of stratospheric ozone depletion a coupled  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAY  a1895-19010 v83 a<p>We report a theoretical investigation on the NOx catalyzed pathways of stratospheric ozone depletion using highly accurate coupled cluster methods. These catalytic reactions represent a great challenge to state-of-the-art ab initio methods, while their mechanisms remain unclear to both experimentalists and theoreticians. In this work, we have used the so-called ``gold standard of quantum chemistry,'' the CCSD(T) method, to identify the saddle points on NOx-based reaction pathways of ozone hole formation. Energies of the saddle points are calculated using the multireference variants of coupled cluster methods. The calculated activation energies and rate constants show good agreement with available experimental results. Tropospheric precursors to stratospheric NOx radicals have been identified, and their potential importance in stratospheric chemistry has been discussed. Our calculations resolve previous conflicts between ab initio and experimental results for a trans nitro peroxide intermediate, in the NOx catalyzed pathway of ozone depletion.</p>1 aDutta, Achintya, Kumar1 aVaval, Nayana1 aPal, Sourav  uhttp://library.ncl.res.in/content/nox-catalyzed-pathway-stratospheric-ozone-depletion-coupled-cluster-investigation-001794nas a2200169   4500008004100000022001400041245015800055210006900213260008700282300002300369490000800392520103500400100002701435700001801462700001601480856012801496       2015                        eng d  a0021-960600aNew scheme for perturbative triples correction to (0,1) sector of Fock space multi-reference coupled cluster method: Theory, implementation, and examples0 aNew scheme for perturbative triples correction to 01 sector of F  a1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScJAN  aArticle No. 0441130 v1423 a<p>We propose a new elegant strategy to implement third order triples correction in the light of many-body perturbation theory to the Fock space multi-reference coupled cluster method for the ionization problem. The computational scaling as well as the storage requirement is of key concerns in any many-body calculations. Our proposed approach scales as N-6 does not require the storage of triples amplitudes and gives superior agreement over all the previous attempts made. This approach is capable of calculating multiple roots in a single calculation in contrast to the inclusion of perturbative triples in the equation of motion variant of the coupled cluster theory, where each root needs to be computed in a state-specific way and requires both the left and right state vectors together. The performance of the newly implemented scheme is tested by applying to methylene, boron nitride (B2N) anion, nitrogen, water, carbon monoxide, acetylene, formaldehyde, and thymine monomer, a DNA base. (C) 2015 AIP Publishing LLC.</p>1 aDutta, Achintya, Kumar1 aVaval, Nayana1 aPal, Sourav  uhttp://library.ncl.res.in/content/new-scheme-perturbative-triples-correction-01-sector-fock-space-multi-reference-coupled-1