Search results for " Triplet"
showing 10 items of 23 documents
Large-scale calculations of excitation energies in coupled cluster theory: The singlet excited states of benzene
1996
Algorithms for calculating singlet excitation energies in the coupled cluster singles and doubles (CCSD) model are discussed and an implementation of an atomic-integral direct algorithm is presented. Each excitation energy is calculated at a cost comparable to that of the CCSD ground-state energy. Singlet excitation energies are calculated for benzene using up to 432 basis functions. Basis-set effects of the order of 0.2 eV are observed when the basis is increased from augmented polarized valence double-zeta (aug-cc-pVDZ) to augmented polarized valence triple-zeta (aug-cc-pVTZ) quality. The correlation problem is examined by performing calculations in the hierarchy of coupled cluster models…
A theoretical insight into the photophysics of psoralen
2006
Psoralen photophysics has been studied on quantum chemistry grounds using the multiconfigurational second-order perturbation method CASPT2. Absorption and emission spectra of the system have been rationalized by computing the energies and properties of the low-lying singlet and triplet excited states. The S1 ππ* state has been determined to be responsible of the lowest absorption and fluorescence bands and to initially carry the population in the photophysical processes related to the phototherapeutic properties of psoralen derivatives. The low-lying T1 ππ* state is, on the other hand, protagonist of the phosphorescence, and its prevalent role in the reactivity of psoralen is suggested to b…
Complete basis set B3LYP NMR calculations of CDCl3solvent's water fine spectral details
2008
The assignment of singlet at 1.55 ppm and the 1:1:1 triplet at 1.519 ppm to H2O and HOD in the 400 MHz 1H NMR spectrum of CDCl3 solvent were supported by complete basis set (CBS) GIAO-B3LYP calculated chemical shift and the CBS B3LYP estimated 2J(D,H) spin–spin coupling constant (SSCC). The CBS fitting of B3LYP/cc-pCVxZ and B3LYP/pcJ-n predicted SSCC values, the accurate value of 2J(D,H) = − 1.082 ± 0.030 Hz of HOD in chloroform-d1 and the H/D isotopic shift of 0.0307(1) ppm were reported for the first time. The agreement between CBS B3LYP predicted chemical shift, spin–spin values and experiment was good. Copyright © 2008 John Wiley & Sons, Ltd.
Neutriinojen sekoitusmatriisin Majorana-vaiheet
2013
Lukuisat hiukkasfysiikan kokeet ovat vahvistaneet neutriinojen olevan massallisia hiukkasia ja kykenevän muuttumaan neutriinotyypistä toiseen. Tätä niin kutsuttua neutriino-oskillaatiota parametrisoi neutriinojen sekoitusmatriisi, jota puolestaan parametrisoi kolmen sekoituskulman lisäksi yksi tai kolme CP-symmetriaa rikkovaa vaihetta riippuen siitä ovatko neutriinot Dirac- tai Majorana-hiukkasia. Tässä työssä tarkasteltiin edellä mainittujen Dirac- ja Majorana-vaiheiden merkitystä neutriino-oskillaatioissa, neutriinonottomassa kaksoisbeetahajoamisessa, Higgsin triplettimallissa ja baryoniepäsymmetrian synnyttäneessä leptonigeneesissä. Neutriino-oskillaation tarkastelua varten johdettiin ne…
Clinical parameters to guide decision-making in elderly metastatic colorectal CANCER patients treated with intensive cytotoxic and anti-angiogenic th…
2017
// Gemma Bruera 1, 2 , Antonio Russo 3 , Antonio Galvano 3 , Sergio Rizzo 3 and Enrico Ricevuto 1, 2 1 Oncology Territorial Care, S. Salvatore Hospital, Oncology Network ASL1 Abruzzo, University of L’Aquila, L’Aquila, Italy 2 Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, L’Aquila, Italy 3 Medical Oncology, Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy Correspondence to: Antonio Russo, email: antonio.russo@usa.net Keywords: elderly, intensive treatment, metastatic colorectal cancer, triplet chemotherapy plus bevacizumab, unfit Received: June 07, 2016 Accepted: November 24, 2016 Published:…
ATXN2 trinucleotide repeat length correlates with risk of ALS
2017
We investigated a CAG trinucleotide repeat expansion in the ATXN2 gene in amyotrophic lateral sclerosis (ALS). Two new case-control studies, a British dataset of 1474 ALS cases and 567 controls, and a Dutch dataset of 1328 ALS cases and 691 controls were analyzed. In addition, to increase power, we systematically searched PubMed for case-control studies published after 1 August 2010 that investigated the association between ATXN2 intermediate repeats and ALS. We conducted a meta-analysis of the new and existing studies for the relative risks of ATXN2 intermediate repeat alleles of between 24 and 34 CAG trinucleotide repeats and ALS. There was an overall increased risk of ALS for those carry…
Ab initio study on the low-lying excited states of retinal
1997
Ab initio results for the electronic spectrum of all-trans-retinal and its truncated model 3-methyl-all-trans (10-s-cis)-2,4,6,8,10-undecapentaen-1-al are presented. The study includes geometry determination of the ground state. Vertical excitation energies have been computed using multiconfigurational second-order perturbation theory through the CASPT2 formalism. The lowest singlet excited state in gas phase is predicted to be of nπ∗ character. The lowest triplet state corresponds, however, to a ππ∗ state. The most intense feature of the spectrum is due to the strongly dipole-allowed ππ∗ transition, in accordance with the observed maximum in the one-photon spectra. The vertical excitation …
Photoluminescence spectral dispersion as a probe of structural inhomogeneity in silica
2011
We perform time-resolved photoluminescence measurements on point defects in amorphous silicon dioxide (silica). In particular, we report data on the decay kinetics of the emission signals of extrinsic oxygen deficient centres of the second type from singlet and directly excited triplet states, and we use them as a probe of structural inhomogeneity. Luminescence activity in sapphire (alpha-Al(2)O(3)) is studied as well and used as a model system to compare the optical properties of defects in silica with those of defects embedded in a crystalline matrix. Only for defects in silica did we observe a variation of the decay lifetimes with emission energy and a time dependence of the first moment…
Analysis of mebendazole binding to its target biomolecule by laser flash photolysis
2016
[EN] Mebendazole (MBZ) and related anticancer benzimidazoles act binding the beta-subunit of Tubulin (TU) before dimerization with alpha-TU with subsequent blocking microtubule formation. Laser flash photolysis (LFP) is a new tool to investigate drug-albumin interactions and to determine binding parameters such as affinity constant or population of binding sites. The aim of this study was to evaluate the interactions between the nonfluorescent mebendazole (MBZ) and its target biomolecule TU using this technique. Before analyzing the MBZ@TU complex it was needed to determine the photophysical properties of MBZ triplet excited state ((3)MBZ*) in different media. Hence, 3MBZ* showed a transien…
Representation Theorems for Solvable Sesquilinear Forms
2017
New results are added to the paper [4] about q-closed and solvable sesquilinear forms. The structure of the Banach space $\mathcal{D}[||\cdot||_\Omega]$ defined on the domain $\mathcal{D}$ of a q-closed sesquilinear form $\Omega$ is unique up to isomorphism, and the adjoint of a sesquilinear form has the same property of q-closure or of solvability. The operator associated to a solvable sesquilinear form is the greatest which represents the form and it is self-adjoint if, and only if, the form is symmetric. We give more criteria of solvability for q-closed sesquilinear forms. Some of these criteria are related to the numerical range, and we analyse in particular the forms which are solvable…