Toward Accurate Characterization of the Puzzling NSO and SNO Moieties DOI
Vincenzo Barone, Lina Uribe, Satyam Srivastav

et al.

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: 8(11), P. 2334 - 2344

Published: Nov. 8, 2024

The structural and spectroscopic properties in the gas phase of prototypical compounds containing NSO SNO moieties have been analyzed by a general computational strategy based on recent Pisa composite schemes (PCS). In first step, an accurate semiexperimental (SE) equilibrium structure has derived for cis-HNSO employed, together with already available SE structures cis- trans-HSNO, to validate geometrical parameters delivered different quantum chemical methods. results confirm accuracy proposed schemes, provided that complementary auxiliary basis set correction is included Hartree–Fock component. However, perturbative inclusion quadruple excitations mandatory obtaining correct S–N bond length case HSNO. this way, it possible obtain ground state rotational constants, employing latter vibrational corrections obtained methods rooted density functional theory (DFT) framework second-order perturbation theory. much cheaper model DFT geometry optimizations one-parameter corrections, while slightly less accurate, represent remarkable improvement respect current comparable cost. nearly identical induced HSNO CH3SNO paves way toward study larger biochemical interest or moieties.

Language: Английский

From Perception to Prediction and Interpretation: Enlightening the Gray Zone of Molecular Bricks of Life With the Help of Machine Learning and Quantum Chemistry DOI Open Access
Vincenzo Barone

Wiley Interdisciplinary Reviews Computational Molecular Science, Journal Year: 2025, Volume and Issue: 15(1)

Published: Jan. 1, 2025

ABSTRACT The latest developments of a general exploration/exploitation strategy for the computational study molecular bricks life in gas‐phase are presented and illustrated by means prototypical semi‐rigid flexible systems. In first step, generalized natural internal coordinates employed to obtain clear‐cut separation between different degrees freedom, machine‐learning algorithms based on chemical descriptors (synthons) drive fast quantum methods exploration rugged potential energy surfaces ruled soft freedom. Then, models carefully selected exploiting energies, geometries, vibrational frequencies with aim maximizing accuracy overall description while retaining reasonable cost all steps. particular, composite wave‐function method is used whereas double‐hybrid functional geometries harmonic cheaper global hybrid anharmonic contributions. A panel containing up 50 atoms show that proposed draws closer state‐of‐the‐art small molecules, but applicable much larger implementation whole workflow terms preprocessing postprocessing data provided standard electronic structure codes paves way toward accurate yet not prohibitively expensive medium‐ large‐sized molecules user‐friendly black‐box tool exploitable also experiment‐oriented researchers.

Language: Английский

Citations

4
Structures and Rotational Constants of Monocyclic Monoterpenes at DFT Cost by Pisa Composite Schemes and Vibrational Perturbation Theory DOI
Federico Lazzari, Lina Uribe, Silvia Di Grande

et al.

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 6, 2025

The structures and rotational constants of prototypical monocyclic terpenes terpenoids have been analyzed by a general computational strategy based on recent Pisa composite schemes (PCS) vibrational perturbation theory at second order (VPT2). Concerning equilibrium geometries, one-parameter empirical correction is added to bond lengths obtained the revDSD-PBEP86 double hybrid functional in conjunction with slightly modified cc-pVTZ-F12 basis set. same set give accurate harmonic frequencies, whereas cheaper B3LYP double-ζ employed compute semidiagonal cubic force needed obtain corrections framework VPT2 model. final results this way show most cases average deviations respect experiment close 0.1%, which correspond errors around 1 mÅ 0.1° for valence angles, respectively. accuracy has produced reliable estimates species not yet experimentally. In addition intrinsic interest studied molecules, article confirms that high-resolution spectroscopic studies quite large systems can now be aided very robust user-friendly tool.

Language: Английский

Citations

2
Accurate Geometries of Large Molecules at DFT Cost by Semiexperimental and Coupled Cluster Templating Fragments DOI
Silvia Di Grande, Federico Lazzari, Vincenzo Barone

et al.

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(20), P. 9243 - 9258

Published: Oct. 7, 2024

Accurate geometries of small semirigid molecules in the gas phase are available thanks to high-resolution spectroscopy and accurate quantum chemical approaches. These results can be employed for validating cheaper low-level models or correcting corresponding structures large molecules. On these grounds, this work, a panel semiexperimental equilibrium already literature is used confirm average error (1 mÅ bond lengths 2 mrad valence angles) version Pisa composite schemes (PCS2), which applicable containing up about 20 atoms. Then, 30 additional medium-sized systems were optimized at PCS2 level cover more balanced space moieties poorly represented SE compilations. The final database on public domain Web site (https://www.skies-village.it/databases/) larger obtained by hybrid double-hybrid density functionals framework templating molecule approach. Several examples show that corrections based building blocks taken from reduce B3LYP geometrical parameters nearly an order magnitude without increasing computational cost. Furthermore, different functional theory (DFT) wave function (e.g., MP2) improved same way simply computing both whole suitable chosen level. whenever reference some atoms not available, they purposely employing reasonable computer resources. Therefore, new DFT-cost tool now characterization experiment-oriented scientists.

Language: Английский

Citations

8
Accurate Vibrational and Ro-Vibrational Contributions to the Properties of Large Molecules by a New Engine Employing Curvilinear Internal Coordinates and Vibrational Perturbation Theory to Second Order DOI
Marco Mendolicchio, Vincenzo Barone

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 31, 2024

The unbiased comparison between theory and experiment requires approaches more sophisticated than the basic harmonic-oscillator rigid-rotor model, for taking into account vibrational averaging effects ro-vibrational couplings in molecules of increasing size. Second-order perturbation based on curvilinear internal coordinates (ICs) offers a remarkable compromise accuracy computational cost, thanks to reduction mode–mode with respect their counterparts Cartesian coordinates. Therefore, we have developed, implemented, validated general engine employing ICs, which allows accurate evaluation averages containing up about 50 atoms beyond harmonic approximation. After validation new tool relatively small molecules, effectiveness ICs has been demonstrated some flexible and/or quite large molecular bricks life.

Language: Английский

Citations

6
Accurate Structures and Spectroscopic Parameters of CN-Substituted Polycyclic Hydrocarbons at DFT Cost DOI
Vincenzo Barone, Federico Lazzari, Silvia Di Grande

et al.

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: March 17, 2025

The structures, isomerization energies, and rotational vibrational spectra of prototypical CN-substituted polycyclic hydrocarbons in the gas phase have been analyzed using a general computational strategy based on Pisa composite schemes (PCS) second-order perturbation theory (VPT2). final results obtained this way show, most cases, relative average deviations with respect to experimental constants close 0.1%, corresponding errors around 1 mÅ 0.1° for bond lengths valence angles, respectively. At same time, fundamental IR absorption bands are reproduced below 10 cm–1 without any scaling factor. In addition intrinsic interest studied molecules, work confirms that spectroscopic studies large systems can be supported by unsupervised tools couple accuracy reasonable cost.

Language: Английский

Citations

0
Molecular structures with spectroscopic accuracy at DFT cost by the templating synthon approach and the PCS141 database DOI
Federico Lazzari, Silvia Di Grande, Luigi Crisci

et al.

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(11)

Published: March 20, 2025

The computation of accurate geometric parameters at density functional theory cost for large molecules in the gas phase is addressed through a novel strategy that combines quantum chemical models with machine learning techniques. first key step expansion database semi-experimental equilibrium structures additional molecular geometries optimized by version 2 Pisa composite scheme. Then, templating synthon approach used to improve accuracy hybrid paired double zeta basis set, leveraging similarity cluster different environments and refine bond lengths valence angles. A set prototypical biomolecular building blocks demonstrate it possible achieve spectroscopic systems too be treated state-of-the-art wavefunction methods. In addition, freely accessible web-based tool has been developed facilitate post-processing using standard electronic structure codes, thereby providing an efficient computational study medium- large-sized molecules, also experiment-oriented researchers.

Language: Английский

Citations

0
Accurate Structure and Spectroscopic Properties of Azulene and Its Derivatives by Means of Pisa Composite Schemes and Vibrational Perturbation Theory to Second Order DOI
Lina Uribe, Silvia Di Grande, Marco Mendolicchio

et al.

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 26, 2024

The structural and spectroscopic properties in the gas phase of azulene some its N-bearing derivatives have been analyzed by a general computational strategy based on recent Pisa composite schemes (PCSs). First all, an accurate semiexperimental equilibrium structure has derived for employed to validate geometrical parameters delivered different quantum chemical methods. Next, isomerization energies (azulene naphthalene, 1-aza-azulene quinoline other isomers) computed explicitly correlated PCS version employing frozen natural orbitals. Accurate geometries obtained cheaper variant double-hybrid functional improved one-parameter bond corrections, with same providing also remarkable harmonic frequencies. corresponding rotational constants show average deviations within 0.1% from experimental results when taking into account anharmonic vibrational corrections global hybrid functional. Therefore, reliable estimates produced several nitrogen (isomeric aza-azulenes guaiazulene), whose non-negligible dipole moments could allow microwave characterizations. An analogous approach delivers infrared spectra agreement their counterparts quinoline, azulene, together predictions still-unknown spectrum 1-aza-azulene. In addition intrinsic interest, this paper further confirm that very yet robust user-friendly tool is now available aiding high-resolution studies quite large systems current technological and/or biological interest.

Language: Английский

Citations

2
Reduced Cost Computation and Exploitation of Accurate Radial Interaction Potentials for Barrier-Less Processes DOI
Luigi Crisci, Bernardo Ballotta, Marco Mendolicchio

et al.

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(21), P. 9435 - 9445

Published: Nov. 1, 2024

Barrier-less steps are typical of radical and ionic reactions in the gas-phase, which often take place extreme environments such as combustion reactors operating at very high temperatures or interstellar medium, characterized by ultralow pressures. The difficulty experimental studies conditions mimicking these suggests that computational approaches can provide a valuable support. In this connection, most advanced treatments processes framework transition state theory able to deliver accurate kinetic parameters provided underlying potential energy surface is sufficiently accurate. Since requires balanced treatment static dynamic correlation (which play different roles regions), sophisticated expensive quantum chemical required. One effective solution problem offered computation one-dimensional radial potentials, then used correct results Monte Carlo sampling performed cheaper approaches. paper, we will show that, for large panel barrier-less reaction steps, ruled

Language: Английский

Citations

0
Toward Accurate Characterization of the Puzzling NSO and SNO Moieties DOI
Vincenzo Barone, Lina Uribe, Satyam Srivastav

et al.

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: 8(11), P. 2334 - 2344

Published: Nov. 8, 2024

The structural and spectroscopic properties in the gas phase of prototypical compounds containing NSO SNO moieties have been analyzed by a general computational strategy based on recent Pisa composite schemes (PCS). In first step, an accurate semiexperimental (SE) equilibrium structure has derived for cis-HNSO employed, together with already available SE structures cis- trans-HSNO, to validate geometrical parameters delivered different quantum chemical methods. results confirm accuracy proposed schemes, provided that complementary auxiliary basis set correction is included Hartree–Fock component. However, perturbative inclusion quadruple excitations mandatory obtaining correct S–N bond length case HSNO. this way, it possible obtain ground state rotational constants, employing latter vibrational corrections obtained methods rooted density functional theory (DFT) framework second-order perturbation theory. much cheaper model DFT geometry optimizations one-parameter corrections, while slightly less accurate, represent remarkable improvement respect current comparable cost. nearly identical induced HSNO CH3SNO paves way toward study larger biochemical interest or moieties.

Language: Английский

Citations

0