scholarly journals Design and synthesis of aromatic molecules for probing electric fields at the nanoscale

2015 ◽  
Vol 184 ◽  
pp. 251-262 ◽  
Author(s):  
Sanli Faez ◽  
Nico R. Verhart ◽  
Marios Markoulides ◽  
Francesco Buda ◽  
André Gourdon ◽  
...  
Keyword(s):  
Electric Fields ◽  
Single Molecule ◽  
Binding Sites ◽  
Density Functional ◽  
Near Infrared ◽  
Organic Dyes ◽  
Single Molecule Spectroscopy ◽  
Functional Theory ◽  
Design And Synthesis ◽  
Aromatic Molecules

We propose using halogenated organic dyes as nanoprobes for electric fields and show their greatly enhanced Stark coefficients using density functional theory (DFT) calculations. We analyse halogenated variants of three molecules that have been of interest for cryogenic single molecule spectroscopy: perylene, terrylene, and dibenzoterrylene, with the zero-phonon optical transitions at blue, red, and near-infrared. Out of all the combinations of halides and binding sites that are calculated, we have found that fluorination of the optimum binding site induces a dipole difference between the ground and excited states larger than 0.5 D for all three molecules with the highest value of 0.69 D for fluoroperylene. We also report on the synthesis of 3-fluoroterrylene and the bulk spectroscopy of this compound in liquid and solid organic environments.

scholarly journals Mono- and Bi-Molecular Adsorption of SF6 Decomposition Products on Pt Doped Graphene: A First-Principles Investigation

2018 ◽  
Vol 8 (10) ◽  
pp. 2010 ◽  
Author(s):  
Yongqian Wu ◽  
Shaojian Song ◽  
Dachang Chen ◽  
Xiaoxing Zhang
Keyword(s):  
Single Molecule ◽  
First Principles ◽  
Density Functional ◽  
Energy Gap ◽  
Adsorption Parameters ◽  
Functional Theory ◽  
Decomposition Products ◽  
Before And After ◽  
Doped Graphene ◽  
Sf6 Decomposition

Based on the first-principles of density functional theory, the SF6 decomposition products including single molecule (SO2F2, SOF2, SO2), double homogenous molecules (2SO2F2, 2SOF2, 2SO2) and double hetero molecules (SO2 and SOF2, SO2 and SO2F2, SOF2 and SO2F2) adsorbed on Pt doped graphene were discussed. The adsorption parameters, electron transfer, electronic properties and energy gap was investigated. The adsorption of SO2, SOF2 and SO2F2 on the surface of Pt-doped graphene was a strong chemisorption process. The intensity of chemical interactions between the molecule and the Pt-graphene for the above three molecules was SO2F2 > SOF2 > SO2. The change of energy gap was also studied and according to the value of energy gap, the conductivity of Pt-graphene before and after adsorbing different gas molecules can be evaluated.

scholarly journals DFT Protocol for EPR Prediction of Paramagnetic Cu(II) Complexes and Application to Protein Binding Sites

2018 ◽  
Vol 4 (4) ◽  
pp. 55 ◽  
Author(s):  
Giuseppe Sciortino ◽  
Giuseppe Lubinu ◽  
Jean-Didier Maréchal ◽  
Eugenio Garribba
Keyword(s):  
Binding Sites ◽  
Density Functional ◽  
Computational Procedure ◽  
Paramagnetic Resonance ◽  
Functional Theory ◽  
Protein Binding Sites ◽  
The Mean ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

With the aim to provide a general protocol to interpret electron paramagnetic resonance (EPR) spectra of paramagnetic copper(II) coordination compounds, density functional theory (DFT) calculations of spin Hamiltonian parameters g and A for fourteen Cu(II) complexes with different charges, donor sets, and geometry were carried out using ORCA software. The performance of eleven functionals was tested, and on the basis of the mean absolute percent deviation (MAPD) and standard deviation (SD), the ranking of the functionals for Az is: B3LYP > B3PW91 ~ B3P86 > PBE0 > CAM-B3LYP > TPSSh > BH and HLYP > B2PLYP > MPW1PW91 > ω-B97x-D >> M06; and for gz is: PBE0 > BH and HLYP > B2PLYP > ω-B97x-D > B3PW91~B3LYP~B3P86 > CAM-B3LYP > TPSSh~MPW1PW91 >> M06. With B3LYP the MAPD with respect to A z exp t l is 8.6% with a SD of 4.2%, while with PBE0 the MAPD with respect to g z exp t l is 2.9% with a SD of 1.1%. The results of the validation confirm the fundamental role of the second order spin-orbit contribution to Az. The computational procedure was applied to predict the values of gz and Az of the adducts formed by Cu(II) with albumin and two fragments of prion protein, 106–126 and 180–193.

Electric Field-induced switching among multiple conductance pathways in single-molecule junctions

2021 ◽  
Author(s):  
Tengyang Gao ◽  
Zhichao Pan ◽  
Zhuanyun Cai ◽  
Jueting Zheng ◽  
Chun Tang ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Single Molecule ◽  
Scanning Tunneling Microscope ◽  
Binding Sites ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
Field Increase ◽  
Electric Field Increase ◽  
Single Molecule Junctions

Here, we report the switching among multiple conductance pathways achieved by sliding the scanning tunneling microscope tip among different binding sites under different electric fields. With the electric field increase,...

scholarly journals Vibrational Dynamics of Crystalline 4-Phenylbenzaldehyde from INS Spectra and Periodic DFT Calculations

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1374
Author(s):  
Mariela M. Nolasco ◽  
Catarina F. Araujo ◽  
Pedro D. Vaz ◽  
Ana M. Amado ◽  
Paulo Ribeiro-Claro
Keyword(s):  
Dft Calculations ◽  
Single Molecule ◽  
Density Functional ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Torsional Mode ◽  
Functional Theory ◽  
Periodic Dft Calculations ◽  
Periodic Calculations ◽  
Unambiguous Assignment

The present work emphasizes the value of periodic density functional theory (DFT) calculations in the assessment of the vibrational spectra of molecular crystals. Periodic calculations provide a nearly one-to-one match between the calculated and observed bands in the inelastic neutron scattering (INS) spectrum of crystalline 4-phenylbenzaldehyde, thus validating their assignment and correcting previous reports based on single molecule calculations. The calculations allow the unambiguous assignment of the phenyl torsional mode at ca. 118–128 cm−1, from which a phenyl torsional barrier of ca. 4000 cm−1 is derived, and the identification of the collective mode involving the antitranslational motion of CH···O bonded pairs, a hallmark vibrational mode of systems where C-H···O contacts are an important feature.

scholarly journals Computationally aided, entropy-driven synthesis of highly efficient and durable multi-elemental alloy catalysts

2020 ◽  
Vol 6 (11) ◽  
pp. eaaz0510 ◽  
Author(s):  
Yonggang Yao ◽  
Zhenyu Liu ◽  
Pengfei Xie ◽  
Zhennan Huang ◽  
Tangyuan Li ◽  
...  
Keyword(s):  
Density Functional ◽  
Rational Design ◽  
Density Functional Theory Calculations ◽  
Great Promise ◽  
Alloy Formation ◽  
Functional Theory ◽  
Excellent Thermal Stability ◽  
Design And Synthesis ◽  
Highly Efficient ◽  
Computational Strategy

Multi-elemental alloy nanoparticles (MEA-NPs) hold great promise for catalyst discovery in a virtually unlimited compositional space. However, rational and controllable synthesize of these intrinsically complex structures remains a challenge. Here, we report the computationally aided, entropy-driven design and synthesis of highly efficient and durable catalyst MEA-NPs. The computational strategy includes prescreening of millions of compositions, prediction of alloy formation by density functional theory calculations, and examination of structural stability by a hybrid Monte Carlo and molecular dynamics method. Selected compositions can be efficiently and rapidly synthesized at high temperature (e.g., 1500 K, 0.5 s) with excellent thermal stability. We applied these MEA-NPs for catalytic NH3 decomposition and observed outstanding performance due to the synergistic effect of multi-elemental mixing, their small size, and the alloy phase. We anticipate that the computationally aided rational design and rapid synthesis of MEA-NPs are broadly applicable for various catalytic reactions and will accelerate material discovery.

Exceptional mechano-electronic properties in the HfN2 monolayer: a promising candidate in low-power flexible electronics, memory devices and photocatalysis

2020 ◽  
Vol 22 (37) ◽  
pp. 21275-21287 ◽  
Author(s):  
Manish Kumar Mohanta ◽  
I. S. Fathima ◽  
Abir De Sarkar
Keyword(s):  
Density Functional Theory ◽  
Low Power ◽  
Electronic Properties ◽  
Electric Fields ◽  
Flexible Electronics ◽  
Density Functional ◽  
External Perturbation ◽  
Density Functional Theory Calculations ◽  
Promising Candidate ◽  
Functional Theory

The response of the electronic properties of the HfN2 monolayer to external perturbation such as strain and electric fields has been investigated using density functional theory calculations for its device-based applications and photocatalysis.

scholarly journals Redox-Active Dysprosium Single-Molecule Magnet: Spectro-Electrochemistry and Theoretical Investigations

2019 ◽  
Vol 5 (3) ◽  
pp. 46 ◽  
Author(s):  
Guglielmo Fernandez Garcia ◽  
Vincent Montigaud ◽  
Lucie Norel ◽  
Olivier Cador ◽  
Boris Le Guennic ◽  
...  
Keyword(s):  
Single Molecule ◽  
Density Functional ◽  
Functional Theory ◽  
Single Molecule Magnet ◽  
Complete Active Space ◽  
Consistent Field ◽  
Redox Active ◽  
Theoretical Investigations ◽  
Td Dft ◽  
Self Consistent Field

The mononuclear single-molecule magnet (SMM) [Dy(tta)3(L)]⋅C6H14 (1) (where tta− = 2-thenoyltrifluoroacetonate and L = 4,5-bis(propylthio)-tetrathiafulvalene-2-(2-pyridyl)benzimidazole-methyl-2-pyridine) was studied by spectro-electrochemistry. The resulting electronic spectra of the three oxidation states 1, 1+∙, and 12+ were rationalized by time-dependent density functional theory (TD-DFT) calculations starting from the DFT optimized structures. The modulation of the magnetic anisotropy of the DyIII center upon oxidation was also inspected at the Complete Active Space Self-Consistent Field (CASSCF) level of calculation.

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