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1. Density Functional Theory for the Photoionization Dynamics of Uracil

Author

Toffoli, D., Decleva, P., Gianturco, F. A., and Lucchese, R. R.

Subjects
Physics - Chemical Physics
Abstract

Photoionization dynamics of the RNA base Uracil is studied in the framework of Density Functional Theory (DFT). The photoionization calculations take advantage of a newly developed parallel version of a multicentric approach to the calculation of the electronic continuum spectrum which uses a set of B-spline radial basis functions and a Kohn-Sham density functional hamiltonian. Both valence and core ionizations are considered. Scattering resonances in selected single-particle ionization channels are classified by the symmetry of the resonant state and the peak energy position in the photoelectron kinetic energy scale; the present results highlight once more the site specificity of core ionization processes. We further suggest that the resonant structures previously characterized in low-energy electron collision experiments are partly shifted below threshold by the photoionization processes. A critical evaluation of the theoretical results providing a guide for future experimental work on similar biosystems.

Published
2007
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4. Safety and efficacy of once-daily risdiplam in type 2 and non-ambulant type 3 spinal muscular atrophy (SUNFISH part 2): a phase 3, double-blind, randomised, placebo-controlled trial

Author

Mercuri, Eugenio Maria, Deconinck, N., Mazzone, Elena Stacy, Nascimento, A., Oskoui, M., Saito, K., Vuillerot, C., Baranello, Giovanni, Boespflug-Tanguy, O., Goemans, N., Kirschner, J., Kostera-Pruszczyk, A., Servais, L., Gerber, M., Gorni, K., Khwaja, O., Kletzl, H., Scalco, R. S., Staunton, H., Yeung, W. Y., Martin, Craig, Fontoura, P., Day, J. W., Volpe, J. J., Posner, J., Kellner, U., Quinlivan, R., Fuerst-Recktenwald, S., Marquet, A., Mulhardt, N., Trundell, D., Daron, A., Delstanche, S., Romain, B., Dal Farra, F., Schneider, O., Balikova, I., Delbeke, P., Joniau, I., Tahon, V., Wittevrongel, S., De Vos, E., Casteels, I., De Waele, L., Cassiman, C., Prove, L., Kinoo, D., Vancampenhout, L., Van Den Hauwe, M., Van Impe, A., Prufer de Queiroz Campos Araujo, A., Chacon Pereira, A., Nardes, F., Haefeli, L., Rossetto, J., Almeida Pereira, J., Ferreira Rebel, M., Campbell, C., Sharan, S., Mcdonald, W., Scholtes, C., Mah, J., Sframeli, M., Chiu, A., Hagel, J., Beneish, R., Pham, C., Toffoli, D., Arpin, S., Turgeon Desilets, S., Wang, Y., Hu, C., Huang, J., Qian, C., Shen, L., Xiao, Y., Zhou, Z., Li, H., Wang, S., Xiong, H., Chang, X., Dong, H., Liu, Y., Sang, T., Wei, C., Wen, J., Cao, Y., Lv, X., Zhao, J., Li, W., Qin, L., Barisic, N., Galiot Delic, M., Ivkic, P. K., Vukojevic, N., Kern, I., Najdanovic, B., Skugor, M., Gidaro, T., Seferian, A., De Lucia, Sara Sofia, Barreau, E., Mnafek, N., Momtchilova, M. M., Peche, H., Valherie, C., Grange, A., Lilien, C., Milascevic, D., Tachibana, S., Ravelli, C., Cardas, R., Vanden Brande, L., Davion, J. -B., Coopman, S., Bouacha, I., Debruyne, P., Defoort, S., Derlyn, G., Leroy, F., Danjoux, L., Guilbaud, J., Desguerre, I., Barnerias, C., Semeraro, M., Bremond-Gignac, D., Bruere, L., Rateaux, M., Deladriere, E., Germa, V., Pereon, Y., Magot, A., Mercie, S., Billaud, F., Le Goff, L., Letellier, G., Portefaix, A., Fontaine, S., De-Montferrand, C., Le-Goff, L., Saidi, M., Bouzid, N., Barriere, A., Tinat, M., Dreesbach, M., Lagreze, W., Michaelis, B., Molnar, F., Seger, D., Vogt, S., Bertini, Enrico Silvio, D'Amico, Adele, Petroni, S., Bonetti, A. M., Carlesi, A., Mizzoni, I., Bruno, C., Priolo, E., Rao, G., Morando, S., Tacchetti, P., Zuffi, A., Comi, G. P., Brusa, R., Corti, Serafino, Daniele, V., Govoni, A., Magri, F., Minorini, V., Osnaghi, S. G., Abbati, F., Fassini, F., Foa, M., Lopopolo, A., Meneri, M., Zoppas, F., Parente, V., Masson, R., Bianchi Marzoli, Stefania, Santarsiero, Rocco Domenico, Garcia Sierra, M., Tremolada, G., Arnoldi, M. T., Vigano, M., Zanin, Renata, Amorelli, Giulia Maria, Barresi, C., D'Amico, Guglielmo, Orazi, Lorenzo, Coratti, Giorgia, Haginoya, K., Kato, A., Morishita, Y., Kira, R., Akiyama, K., Goto, M., Mori, Y., Okamoto, M., Tsutsui, S., Takatsuji, Y., Tanaka, A., Komaki, H., Suzuki, I., Takeuchi, M., Todoroki, D., Watanabe, S., Omori, M., Matsubayashi, T., Inakazu, E., Nagura, H., Suzuki, A., Osaka, H., Ohashi, M., Ishikawa, N., Harada, Y., Fudeyasu, K., Hirata, K., Michiue, K., Ueda, K., Yashiro, S., Seki, M., Sano, N., Uemura, A., Fukuyama, K., Matsumoto, Y., Miyazaki, H., Shibata, M., Kobayashi, K., Nakamura, Y., Takeshima, Y., Kuma, M., Fraczek, A., Jedrzejowska, M., Lusakowska, A., Czeszyk-Piotrowicz, A., Hautz, W., Rakusiewicz, K., Burlewicz, M., Gierlak-Wojcicka, Z., Kepa, M., Sikorski, A., Sobieraj, M., Mazurkiewicz-Beldzinska, M., Lemska, A., Modrzejewska, S., Koberda, M., Stodolska-Koberda, U., Waskowska, A., Kolendo, J., Sobierajska-Rek, A., Steinborn, B., Dalz, M., Grabowska, J., Hajduk, W., Janasiewicz-Karachitos, J., Klimas, M., Stopa, M., Gajewska, E., Pusz, B., Vlodavets, D., Melnik, E., Leppenen, N., Yupatova, N., Monakhova, A., Papina, Y., Shidlovsckaia, O., Milic Rasic, V., Brankovic, V., Kosac, A., Djokic, O., Jaksic, V., Pepic, A., Martinovic, J., Munell Casadesus, F., Tizzano, E., Martin Begue, N., Wolley Dod, C., Subira, O., Planas Pascual, B., Toro Tamargo, E., Madruga Garrido, M., Medina Romero, J. D., Salinas, M. P., Nascimento Osorio, A., Diaz Cortes, A., Jimenez Ganan, E., Suh, S. D., Medina Cantillo, J., Moya, O., Padros, N., Roca Urraca, S., Gonzalez Valdivia, H., Pascual Pascual, S., de Manuel, S., Noval Martin, S., Burnham, P., Espinosa Garcia, S., Martinez Moreno, M., Topaloglu, H., Oncel, I., Eroglu Ertugrul, N., Konuskan, B., Eldem, B., Kadayifcilar, S., Alemdaroglu, I., Ayse Karaduman, A., Tunca Yilmaz, O., Bilgin, N., Sari, S., Chiriboga, C., Kane, S., Lee, J., Rome-Martin, D., Beres, S., Duong, T., Gee, R., Dunaway Young, S., Mercuri E. (ORCID:0000-0002-9851-5365), Mazzone E. S., Baranello G., Martin C., De Lucia S., Bertini E., D'Amico A., Corti S., Bianchi Marzoli S., Santarsiero D., Zanin R., Amorelli G. M., D'Amico G., Orazi L., Coratti G. (ORCID:0000-0001-6666-5628), Mercuri, Eugenio Maria, Deconinck, N., Mazzone, Elena Stacy, Nascimento, A., Oskoui, M., Saito, K., Vuillerot, C., Baranello, Giovanni, Boespflug-Tanguy, O., Goemans, N., Kirschner, J., Kostera-Pruszczyk, A., Servais, L., Gerber, M., Gorni, K., Khwaja, O., Kletzl, H., Scalco, R. S., Staunton, H., Yeung, W. Y., Martin, Craig, Fontoura, P., Day, J. W., Volpe, J. J., Posner, J., Kellner, U., Quinlivan, R., Fuerst-Recktenwald, S., Marquet, A., Mulhardt, N., Trundell, D., Daron, A., Delstanche, S., Romain, B., Dal Farra, F., Schneider, O., Balikova, I., Delbeke, P., Joniau, I., Tahon, V., Wittevrongel, S., De Vos, E., Casteels, I., De Waele, L., Cassiman, C., Prove, L., Kinoo, D., Vancampenhout, L., Van Den Hauwe, M., Van Impe, A., Prufer de Queiroz Campos Araujo, A., Chacon Pereira, A., Nardes, F., Haefeli, L., Rossetto, J., Almeida Pereira, J., Ferreira Rebel, M., Campbell, C., Sharan, S., Mcdonald, W., Scholtes, C., Mah, J., Sframeli, M., Chiu, A., Hagel, J., Beneish, R., Pham, C., Toffoli, D., Arpin, S., Turgeon Desilets, S., Wang, Y., Hu, C., Huang, J., Qian, C., Shen, L., Xiao, Y., Zhou, Z., Li, H., Wang, S., Xiong, H., Chang, X., Dong, H., Liu, Y., Sang, T., Wei, C., Wen, J., Cao, Y., Lv, X., Zhao, J., Li, W., Qin, L., Barisic, N., Galiot Delic, M., Ivkic, P. K., Vukojevic, N., Kern, I., Najdanovic, B., Skugor, M., Gidaro, T., Seferian, A., De Lucia, Sara Sofia, Barreau, E., Mnafek, N., Momtchilova, M. M., Peche, H., Valherie, C., Grange, A., Lilien, C., Milascevic, D., Tachibana, S., Ravelli, C., Cardas, R., Vanden Brande, L., Davion, J. -B., Coopman, S., Bouacha, I., Debruyne, P., Defoort, S., Derlyn, G., Leroy, F., Danjoux, L., Guilbaud, J., Desguerre, I., Barnerias, C., Semeraro, M., Bremond-Gignac, D., Bruere, L., Rateaux, M., Deladriere, E., Germa, V., Pereon, Y., Magot, A., Mercie, S., Billaud, F., Le Goff, L., Letellier, G., Portefaix, A., Fontaine, S., De-Montferrand, C., Le-Goff, L., Saidi, M., Bouzid, N., Barriere, A., Tinat, M., Dreesbach, M., Lagreze, W., Michaelis, B., Molnar, F., Seger, D., Vogt, S., Bertini, Enrico Silvio, D'Amico, Adele, Petroni, S., Bonetti, A. M., Carlesi, A., Mizzoni, I., Bruno, C., Priolo, E., Rao, G., Morando, S., Tacchetti, P., Zuffi, A., Comi, G. P., Brusa, R., Corti, Serafino, Daniele, V., Govoni, A., Magri, F., Minorini, V., Osnaghi, S. G., Abbati, F., Fassini, F., Foa, M., Lopopolo, A., Meneri, M., Zoppas, F., Parente, V., Masson, R., Bianchi Marzoli, Stefania, Santarsiero, Rocco Domenico, Garcia Sierra, M., Tremolada, G., Arnoldi, M. T., Vigano, M., Zanin, Renata, Amorelli, Giulia Maria, Barresi, C., D'Amico, Guglielmo, Orazi, Lorenzo, Coratti, Giorgia, Haginoya, K., Kato, A., Morishita, Y., Kira, R., Akiyama, K., Goto, M., Mori, Y., Okamoto, M., Tsutsui, S., Takatsuji, Y., Tanaka, A., Komaki, H., Suzuki, I., Takeuchi, M., Todoroki, D., Watanabe, S., Omori, M., Matsubayashi, T., Inakazu, E., Nagura, H., Suzuki, A., Osaka, H., Ohashi, M., Ishikawa, N., Harada, Y., Fudeyasu, K., Hirata, K., Michiue, K., Ueda, K., Yashiro, S., Seki, M., Sano, N., Uemura, A., Fukuyama, K., Matsumoto, Y., Miyazaki, H., Shibata, M., Kobayashi, K., Nakamura, Y., Takeshima, Y., Kuma, M., Fraczek, A., Jedrzejowska, M., Lusakowska, A., Czeszyk-Piotrowicz, A., Hautz, W., Rakusiewicz, K., Burlewicz, M., Gierlak-Wojcicka, Z., Kepa, M., Sikorski, A., Sobieraj, M., Mazurkiewicz-Beldzinska, M., Lemska, A., Modrzejewska, S., Koberda, M., Stodolska-Koberda, U., Waskowska, A., Kolendo, J., Sobierajska-Rek, A., Steinborn, B., Dalz, M., Grabowska, J., Hajduk, W., Janasiewicz-Karachitos, J., Klimas, M., Stopa, M., Gajewska, E., Pusz, B., Vlodavets, D., Melnik, E., Leppenen, N., Yupatova, N., Monakhova, A., Papina, Y., Shidlovsckaia, O., Milic Rasic, V., Brankovic, V., Kosac, A., Djokic, O., Jaksic, V., Pepic, A., Martinovic, J., Munell Casadesus, F., Tizzano, E., Martin Begue, N., Wolley Dod, C., Subira, O., Planas Pascual, B., Toro Tamargo, E., Madruga Garrido, M., Medina Romero, J. D., Salinas, M. P., Nascimento Osorio, A., Diaz Cortes, A., Jimenez Ganan, E., Suh, S. D., Medina Cantillo, J., Moya, O., Padros, N., Roca Urraca, S., Gonzalez Valdivia, H., Pascual Pascual, S., de Manuel, S., Noval Martin, S., Burnham, P., Espinosa Garcia, S., Martinez Moreno, M., Topaloglu, H., Oncel, I., Eroglu Ertugrul, N., Konuskan, B., Eldem, B., Kadayifcilar, S., Alemdaroglu, I., Ayse Karaduman, A., Tunca Yilmaz, O., Bilgin, N., Sari, S., Chiriboga, C., Kane, S., Lee, J., Rome-Martin, D., Beres, S., Duong, T., Gee, R., Dunaway Young, S., Mercuri E. (ORCID:0000-0002-9851-5365), Mazzone E. S., Baranello G., Martin C., De Lucia S., Bertini E., D'Amico A., Corti S., Bianchi Marzoli S., Santarsiero D., Zanin R., Amorelli G. M., D'Amico G., Orazi L., and Coratti G. (ORCID:0000-0001-6666-5628)

Abstract

Background: Risdiplam is an oral small molecule approved for the treatment of patients with spinal muscular atrophy, with approval for use in patients with type 2 and type 3 spinal muscular atrophy granted on the basis of unpublished data. The drug modifies pre-mRNA splicing of the SMN2 gene to increase production of functional SMN. We aimed to investigate the safety and efficacy of risdiplam in patients with type 2 or non-ambulant type 3 spinal muscular atrophy. Methods: In this phase 3, randomised, double-blind, placebo-controlled study, patients aged 2–25 years with confirmed 5q autosomal recessive type 2 or type 3 spinal muscular atrophy were recruited from 42 hospitals in 14 countries across Europe, North America, South America, and Asia. Participants were eligible if they were non-ambulant, could sit independently, and had a score of at least 2 in entry item A of the Revised Upper Limb Module. Patients were stratified by age and randomly assigned (2:1) to receive either daily oral risdiplam, at a dose of 5·00 mg (for individuals weighing ≥20 kg) or 0·25 mg/kg (for individuals weighing <20 kg), or daily oral placebo (matched to risdiplam in colour and taste). Randomisation was conducted by permutated block randomisation with a computerised system run by an external party. Patients, investigators, and all individuals in direct contact with patients were masked to treatment assignment. The primary endpoint was the change from baseline in the 32-item Motor Function Measure total score at month 12. All individuals who were randomly assigned to risdiplam or placebo, and who did not meet the prespecified missing item criteria for exclusion, were included in the primary efficacy analysis. Individuals who received at least one dose of risdiplam or placebo were included in the safety analysis. SUNFISH is registered with ClinicalTrials.gov, NCT02908685. Recruitment is closed; the study is ongoing. Findings: Between Oct 9, 2017, and Sept 4, 2018, 180 patients were rand

Published
2022

8. S2p core level spectroscopy of short chain oligothiophenes.

Author

Baseggio, O., Toffoli, D., Stener, M., Fronzoni, G., de Simone, M., Grazioli, C., Coreno, M., Guarnaccio, A., Santagata, A., and D'Auria, M.

Subjects
*OLIGOTHIOPHENES, *EPIGALLOCATECHIN gallate, *CHAIN length (Chemistry), *X-ray photoelectron spectroscopy, *INFRARED spectroscopy
Abstract

The Near-Edge X-ray-Absorption Fine-Structure (NEXAFS) and X-ray Photoemission Spectroscopy (XPS) of short-chain oligothiophenes (thiophene, 2,20-bithiophene, and 2,20:50,200-terthiophene) in the gas phase have been measured in the sulfur L2,3-edge region. The assignment of the spectral features is based on the relativistic two-component zeroth-order regular approximation time dependent density functional theory approach. The calculations allow us to estimate both the contribution of the spin-orbit splitting and of the molecular-field splitting to the sulfur binding energies and give results in good agreement with the experimental measurements. The deconvolution of the calculated S2p NEXAFS spectra into the two manifolds of excited states converging to the LIII and LII edges facilitates the attribution of the spectral structures. The main S2p NEXAFS features are preserved along the series both as concerns the energy positions and the nature of the transitions. This behaviour suggests that the electronic and geometrical environment of the sulfur atom in the three oligomers is relatively unaffected by the increasing chain length. This trend is also observed in the XPS spectra. The relatively simple structure of S2p NEXAFS spectra along the series reflects the localized nature of the virtual states involved in the core excitation process. [ABSTRACT FROM AUTHOR]

Published
2017
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11. S 2p and P 2p Core Level Spectroscopy of PPT Ambipolar Material and Its Building Block Moieties

Author

Bernes, E., Fronzoni, G., Stener, M., Guarnaccio, A., Zhang, T., Grazioli, C., Johansson, Fredrik, Coreno, M., de Simone, M., Puglia, Carla, Toffoli, D., Bernes, E., Fronzoni, G., Stener, M., Guarnaccio, A., Zhang, T., Grazioli, C., Johansson, Fredrik, Coreno, M., de Simone, M., Puglia, Carla, and Toffoli, D.

Abstract

The near-edge X-ray absorption fine structure (NEXAFS and X-ray photoelectron (XP) spectra of gas-phase 2,8-bis-(diphenylphosphoryl)dibenzo[b,d]thiophene (PPT) and triphenylphosphine oxide (TPPO) have been measured at the S and P L-II,L-III-edge regions. The time-dependent density functional theory (TDDFT) based on the relativistic two-component zeroth-order regular approximation approach has been used to provide an assignment of the experimental spectra, giving the contribution of the spin-orbit splitting and of the molecular-field splitting to the sulfur and phosphor binding energies. Computed XP and NEXAFS spectra agree well with the experimental measurements. In going from dibenzothiophene and TPPO to PPT, the nature of the most intense S 2p and P 2p NEXAFS features are preserved; this trend suggests that the electronic and geometric behaviors of the S and P atoms in the two building block moieties are conserved in the more complex system of PPT. This work enables us to shed some light onto the structure of the P-O bond, a still highly debated topic in the chemical literature. Since the S 2p and P 2p NEXAFS intensities provide specific information on the higher-lying localized sigma*(C-S) and sigma*(P-O) virtual MOs, we have concluded that P 3d AOs are not involved in the formation of the P-O bond. Moreover, the results support the mechanism of negative hyperconjugation, by showing that transitions toward sigma*(P-O) states occur at lower energies with respect to those toward it pi*(P-O) states.

Published
2020
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13. Towards understanding the electronic structure and ion fragmentation patterns of indole and related compounds

Author

Sa’adeh, H, primary, Plekan, O, additional, Ponzi, A, additional, Toffoli, D, additional, Bolognesi, P, additional, Chiarinelli, J, additional, Castrovilli, M C, additional, Vozzi, C, additional, Faccialà, D, additional, Devetta, M, additional, Ciavardini, A, additional, Avaldi, L, additional, Coreno, M, additional, Callegari, C, additional, Richter, R, additional, and Prince, K C, additional

Published
2020
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16. Electronic Structure Characterization of a Thiophene Benzo-Annulated Series of Common Building Blocks for Donor and Acceptor Compounds Studied by Gas Phase Photoelectron and Photoabsorption Synchrotron Spectroscopies

Author

Toffoli, D., primary, Guarnaccio, A., additional, Grazioli, C., additional, Zhang, T., additional, Johansson, F., additional, de Simone, M., additional, Coreno, M., additional, Santagata, A., additional, D’Auria, M., additional, Puglia, C., additional, Bernes, E., additional, Stener, M., additional, and Fronzoni, G., additional

Published
2018
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17. Automatic generation of potential energy and property surfaces of polyatomic molecules in normal coordinates.

Author

Toffoli, D., Kongsted, J., and Christiansen, O.

Subjects
*ELECTRONIC structure, *ELECTRONICS, *ALGORITHMS, *GEARING machinery, *COORDINATES
Abstract

A procedure for the automatic construction of Born-Oppenheimer (BO) potential energy and molecular property surfaces in rectilinear normal coordinates is presented and its suitability and accuracy when combined with vibrational structure calculations are assessed. The procedure relies on a hierarchical n-mode representation of the BO potential energy or molecular property surface, where the n-mode term of the sequence of potentials/molecular properties includes only the couplings between n or less vibrational degrees of freedom. Each n-mode cut of the energy/molecular property surface is first evaluated in a grid of points with ab initio electronic structure methods. The ab initio data are then spline interpolated and a subsequent polynomial fitting provides an analytical semiglobal representation for use in vibrational structure programs. The implementation of the procedure is outlined and the accuracy of the method is tested on water and difluoromethane. Strategies for improving the proposed algorithm are also discussed. [ABSTRACT FROM AUTHOR]

Published
2007
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18. Photoionization cross section and angular distribution calculations of carbon tetrafluoride.

Author

Toffoli, D., Stener, M., Fronzoni, G., and Decleva, P.

Subjects
*CARBON tetrachloride, *PHOTOIONIZATION, *ATOMIC orbitals, *PHOTOCHEMISTRY, *IONIZATION (Atomic physics), *TETRACHLORIDES
Abstract

Correlation in the photoionization dynamics of carbon tetrafluoride is studied in the framework of the time-dependent density-functional theory (TDDFT) approach by employing a multicentric basis set expansion of the scattering wave function linear combination of atomic orbitals (LCAO) TDDFT. Results obtained with the statistical average of orbital potentials and LB94 exchange-correlation (xc) potentials are compared with photoabsorption, photoionization, and electron-scattering experiments as well as with past theoretical calculations. Inadequacies in both the Vxc parametrizations employed have been suggested from the analysis of the intensity plots for the D 2A1 ionization. The formation of resonant scattering states in selected continuum channels has been studied through the analysis of the dipole-prepared scattering wave function; our findings are then compared with results of electron-scattering calculations. Overall, the LCAO-TDDFT results highlight the effectiveness of the approach for the calculation of the unbound spectrum of fairly large molecules. [ABSTRACT FROM AUTHOR]

Published
2006
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19. Time dependent density functional study of the photoionization dynamics of SF6.

Author

Stener, M., Toffoli, D., Fronzoni, G., and Decleva, P.

Subjects
*SPLINE theory, *ATOMIC orbitals, *PHOTOIONIZATION, *DYNAMICS, *DENSITY functionals, *FUNCTIONAL analysis, *STATISTICAL correlation, *AUGER effect, *ANGULAR momentum (Nuclear physics)
Abstract

The B-spline linear combination of atomic orbitals method has been employed to study the valence and core photoionization dynamics of SF6. The cross section and asymmetry parameter profiles calculated at the time dependent density functional theory level have been found to be in fairly nice agreement with the experimental data, with the quality of the exchange-correlation statistical average of orbital potential results superior to the Van Leeuwen-Baerends 94 (LB94) ones [Phys. Rev. A 49, 2421 (1994)]. The role of response effects has been identified by a comparison of the time dependent density functional theory results with the Kohn-Sham ones interchannel coupling effects and autoionization resonances play an important role at low kinetic energies. Prominent shape resonances features have been analyzed in terms of “dipole prepared” continuum orbitals and interpreted as due to a large angular momentum centrifugal barrier as well as anisotropic (nonspherical) molecular effective potential. Finally, the method has been proven numerically stable, robust, and efficient, thanks to a noniterative implementation of the time dependent density functional theory equations and suitability of the multicentric B-spline basis set to describe continuum states from outer valence to deep core states. [ABSTRACT FROM AUTHOR]

Published
2006
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20. Time dependent density functional study of the photoionization dynamics of SF6.

Author

Stener, M., Toffoli, D., Fronzoni, G., and Decleva, P.

Subjects
SPLINE theory, ATOMIC orbitals, PHOTOIONIZATION, DYNAMICS, DENSITY functionals, FUNCTIONAL analysis, STATISTICAL correlation, AUGER effect, ANGULAR momentum (Nuclear physics)
Abstract

The B-spline linear combination of atomic orbitals method has been employed to study the valence and core photoionization dynamics of SF6. The cross section and asymmetry parameter profiles calculated at the time dependent density functional theory level have been found to be in fairly nice agreement with the experimental data, with the quality of the exchange-correlation statistical average of orbital potential results superior to the Van Leeuwen-Baerends 94 (LB94) ones [Phys. Rev. A 49, 2421 (1994)]. The role of response effects has been identified by a comparison of the time dependent density functional theory results with the Kohn-Sham ones interchannel coupling effects and autoionization resonances play an important role at low kinetic energies. Prominent shape resonances features have been analyzed in terms of “dipole prepared” continuum orbitals and interpreted as due to a large angular momentum centrifugal barrier as well as anisotropic (nonspherical) molecular effective potential. Finally, the method has been proven numerically stable, robust, and efficient, thanks to a noniterative implementation of the time dependent density functional theory equations and suitability of the multicentric B-spline basis set to describe continuum states from outer valence to deep core states. [ABSTRACT FROM AUTHOR]

Published
2006
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21. Electronic Structure Characterization of a Thiophene Benzo-Annulated Series of Common Building Blocks for Donor and Acceptor Compounds Studied by Gas Phase Photoelectron and Photoabsorption Synchrotron Spectroscopies

Author

Toffoli, D., Guarnaccio, A., Grazioli, C., Zhang, Teng, Johansson, Fredrik, de Simone, M., Coreno, M., Santagata, A., D’Auria, M., Puglia, Carla, Bernes, E., Stener, M., Fronzoni, G., Toffoli, D., Guarnaccio, A., Grazioli, C., Zhang, Teng, Johansson, Fredrik, de Simone, M., Coreno, M., Santagata, A., D’Auria, M., Puglia, Carla, Bernes, E., Stener, M., and Fronzoni, G.

Abstract

The near-edge x-ray-absorption fine-structure (NEXAFS) and Xray photoelectron spectroscopy (XPS) spectra of benzo[b]thiophene (BBT) and dibenzothiophene (DBT) in the gas phase have been measured at the carbon Kedge and sulfur L-II,L-III-edge regions. The assignment of the spectral features has been provided by theoretical calculations based on density functional theory (DFT) and its time-dependent generalization (TDDFT) in the linear response regime. Observed trends in computed C 1s and S 2p ionization potentials (IPs) have been rationalized in terms of both the inductive effects due to the presence of S and the increased pi-electrons delocalization arising from the benzoannulation process. The analysis of the NEXAFS carbon K-edge and sulfur L-II,L-III-edge regions regions provided information on both low-lying delocalized virtual pi orbitals, and higher-lying localized sigma*(C-S) states. The evolution of the NEXAFS carbon K-edge spectral features along the series thiophene (T) and derivatives, BBT and DBT, is informative of a stabilizing effect due to increased aromaticity. This effect is however more pronounced in going from T to BBT compared to the introduction of a second annulated phenyl ring in DBT. The nature of the most intense sulfur L-II,L-III-edge NEXAFS spectral features is instead conserved along the series reflecting thus the localized nature of the virtual states involved in the S 2p core-excitation process.

Published
2018
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22. Multiscale Self-Assembly of Quantum Dots into an Anisotropic Three-Dimensional Random Network

Author

Ilday, S., Ilday, F., Hübner, R., Prosa, T., Martin, I., Nogay, G., Kabacelik, I., Mics, Z., Turchinovich, D., Ustunel, H., Toffoli, D., Friedrich, D., Schmidt, B., Heinig, K.-H., and Turan, R.

Abstract

One of the well-known challenges in design of nanomaterials is to simultaneously achieve material properties pertaining to few-atom scale and bulk properties through which the material connects to other materials or interacts with devices. This is difficult because properties arising from physics at different scales are often mutually exclusive. An important example is the 30 year-old problem of realizing a connected-but-confined Si nanostructure embedded in a dielectric matrix (e.g., SiO2) that simultaneously brings together quantum-dot (QD)-like optical properties and good electrical conduction. Here, we solve this problem through creation of a hierarchically self-assembled anisotropic random network of Si QDs: At the atomic scale, QDs are formed, which sparsely interconnect without inflating their diameters to form an isotropic random network, and larger scales, this network becomes anisotropic, preferentially growing in the vertical direction to form nanowire-like structures. We report simultaneous achievement of good electrical conductivity (~0.1 S/cm) and a bandgap tuneable over the visible light range (from 1.8 to 2.7 eV). In order to determine how to self-assemble such a topology without using advanced control over dynamical details of the system, we developed a toy model of the stochastic deposition process, from which we related the intended topology to parameters governing stochastic growth and determined the experimental conditions that can give rise to it. Monte Carlo and Molecular Dynamics simulations are performed to guide our methodology and fabrication was done using magnetron sputter deposition. The two leverages that we used for multiscale self-assembly were as follows: (i) We keep the substrate “cold” and adjust how “hot” the deposited particles are. This way, we create spatio-temporal temperature gradients on the surface and thereby, we control surface diffusion and promote vertical growth in the microscale resembling nanowires. (ii) We fine-tune the thin-film stoichiometry in order to control the phase-separation. This way, we control the nominally unstable medium that QDs are embedded in and limit further inflation of their diameters in the atomic scale. This way we show that self-assembly under nonequilibrium conditions and nonlinear dynamics sweeps aside a large number of factors that influence the details of thin-film growth, but provides a couple of simple “rules” (with clearly identifiable corresponding experimental conditions) to determine the final morphology. The generality and material-independence of this methodology is strongly suggestive of possibility to apply it to solve a variety of other nanomaterial problems, which also pertain to multiple scales.

Published
2016

23. Photoelectron diffraction in methane probed via vibrationally resolved inner-valence photoionization cross-section ratios

Author

Nandi S., Plésiat E., Patanen M., Miron C., Bozek J.D., Martín F., Toffoli D., Decleva P. and The experiment was performed at the PL?IADES beamline of the Synchrotron SOLEIL in France (proposal number 99140154 and 99140124). SN thanks E. Antonsson, and C. Nicolas for many fruitful discussions, E. Robert for his technical assistance, and SOLEIL staff for smooth operation of the machine. EP and FM acknowledge financial support from the European Research Council Advanced Grant No. XCHEM 290853, the MINECO project FIS2013-42002-R, and the European COST Action XLIC CM1204. They also acknowledge allocation of computer time from Mare Nostrum BSC and CCC-UAM.

Published
2016

24. Time Dependent Density Functional investigation of the near-edge absorption spectra of V2O5

Author

DE FRANCESCO R, STENER M, TOFFOLI D, FRONZONI G., CAUSA', Mauro, DE FRANCESCO, Renato, Stener, Mauro, M., Causà, Toffoli, Daniele, Fronzoni, Giovanna, DE FRANCESCO, R, Stener, M, Causa', Mauro, Toffoli, D, and Fronzoni, G.

Subjects
NEXAFS, V2O5, CORRECT ASYMPTOTIC-BEHAVIOR, TDDFT, X-RAY-ABSORPTION, TRANSITION-METAL COMPOUNDS, ENERGY-LOSS SPECTRA, OXYGEN K-EDGE
Abstract

We have performed Time Dependent Density Functional Theory (TDDFT) calculations employing a cluster model of the core excitation spectra of vanadium pentoxide, V2O5. The excitation energies and dipole transition moments are determined for all the core edges, vanadium and oxygen K- and vanadium L-edges, treating them at the same level of accuracy. The agreement between the TDDFT theoretical spectra and the experimental data is rather good, particularly at the V and O K-edges. A quantitative reproduction of the fine pre-edge structures appears more difficult for the V L-edge. The comparison between the TDDFT results and the results obtained at the simpler one electron Kohn-Sham (KS) level indicates that the V and O K edges can be correctly described within a single particle approximation (KS), while the strong modi. cation of the V L-edge structures from the KS to the TDDFT description emphasizes the importance of configuration mixing to treat the metal 2p excitations. The origin of the calculated pre-edge features is analyzed in detail with the help of the atom-projected density-of-states of the unoccupied levels. This analysis emphasizes the V 3d dominant character of the final states in the conduction band, probed by the V L-absorption. The strong octahedral distortion of the V2O5 structure allows the mixing of the 3d state with the V 4p components, which are mapped by the oscillator strength in the V K- edge spectrum. The high intensity of the O 1s transitions reflects the presence of a significant O 2p component in the conduction band.

Published
2006

26. Multiscale Self-Assembly of Silicon Quantum Dots into an Anisotropic Three-Dimensional Random Network

Author

Ilday, S., Ilday, F. O., Hübner, R., Prosa, T. J., Martin, I., Nogay, G., Kabacelik, I., Mics, Z., Bonn, M., Turchinovich, D., Toffoli, H., Toffoli, D., Friedrich, D., Schmidt, B., Heinig, K.-H., Turan, R., Ilday, S., Ilday, F. O., Hübner, R., Prosa, T. J., Martin, I., Nogay, G., Kabacelik, I., Mics, Z., Bonn, M., Turchinovich, D., Toffoli, H., Toffoli, D., Friedrich, D., Schmidt, B., Heinig, K.-H., and Turan, R.

Abstract

Multiscale self-assembly is ubiquitous in nature but its deliberate use to synthesize multifunctional three-dimensional materials remains rare, partly due to the notoriously difficult problem of controlling topology from atomic to macroscopic scales to obtain intended material properties. Here, we propose a simple, modular, noncolloidal methodology that is based on exploiting universality in stochastic growth dynamics and driving the growth process under far-from-equilibrium conditions toward a preplanned structure. As proof of principle, we demonstrate a confined-butconnected solid structure, comprising an anisotropic random network of silicon quantum-dots that hierarchically self-assembles from the atomic to the microscopic scales. First, quantum-dots form to subsequently interconnect without inflating their diameters to form a random network, and this network then grows in a preferential direction to form undulated and branching nanowire-like structures. This specific topology simultaneously achieves two scale-dependent features, which were previously thought to be mutually exclusive: good electrical conduction on the microscale and a bandgap tunable over a range of energies on the nanoscale.

Published
2016

28. The dipole and non-dipole parameters of the N K shell of the N-2 molecule up to 80 eV above threshold

Author

Bolognesi, P, Toffoli, D, Decleva, P, Feyer, V, Pravica, L, and Avaldi, L

Subjects
PHOTOELECTRON ANGULAR-DISTRIBUTIONS, IONIZATION, PHOTOEMISSION, APPROXIMATION
Abstract

The contribution of the dipole and non-dipole terms to the angular distribution of the photoelectrons from the N K shell of randomly oriented N-2 molecules has been measured up to 80 eV above the N 1s threshold. The results are compared with all the previous experimental data and theoretical results. Consistently with the predictions of calculations performed in the frame of density functional theory (Toffoli and Decleva 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2681) and in the random phase approximation (Hosaka et al 2006 J. Phys. B: At. Mol. Opt. Phys. 39 L25) the present data show that the non-dipole effects are rather small in the region investigated.

Published
2008

30. Symmetry- And multiplet-resolved N 1s photoionization cross sections of the NO2 molecule

Author

Saito, N., Toffoli, D., Lucchese, R. R., Nagoshi, M., De Fanis, A., Tamenori, Y., Oura, M., Yamaoka, H., Kitajima, M., Tanaka, H., Hergenhahn, U., Ueda, K., Saito, N, Toffoli, Daniele, Lucchese, R. R., Nagoshi, M., De Fanis, A., Tamenori, Y., Oura, M., Yamaoka, H., Kitajima, M., Tanaka, H., Hergenhahn, U., and Ueda, K.

Subjects
Physics and Astronomy (all), Atomic and Molecular Physics, and Optic, Atomic and Molecular Physics, Atomic and Molecular Physics, and Optics, and Optics
Abstract

We present a joint theoretical and experimental investigation of the N 1s photoionization of NO2 in the shape resonance region. The theoretical calculations, based on a single-channel relaxed-core Hartree-Fock approximation, predict that the shape resonance appears only in the A(1)-->B-2 transition and that the shape resonance energy of the N 1s(-1) (1)A(1) channel is about 2.6 eV lower in kinetic energy than that of the N 1s(-1) (3)A(1) channel, suggesting that the potential for the (1)A(1) channel is much more attractive than that for the (3)A(1) channel. Symmetry-selected cross sections measured by means of a multiple-ion coincidence imaging prove that the shape resonance appears only in the A(1)-->B-2 transition, as predicted by the calculation. The experimental partial cross sections for the N 1s(-1) (1)A(1) and (3)A(1) channels measured by means of conventional electron spectroscopy exhibit the shape-resonance maxima at photon energies of 416.3 and 415.9 eV, respectively, at corresponding kinetic energies of 3.0 and 3.3 eV, respectively, implying that the attractive potential for the (1)A(1) channel is overestimated in the single-channel approximation. The possible role played by correlation effects on the K-shell ionization of NO2 is discussed in terms of interchannel coupling between the main-line channels and, possibly, with additional excited target states.

Published
2004

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