scholarly journals A Critical Evaluation of Vibrational Stark Effect (VSE) Probes with the Local Vibrational Mode Theory

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2358 ◽  
Author(s):  
Niraj Verma ◽  
Yunwen Tao ◽  
Wenli Zou ◽  
Xia Chen ◽  
Xin Chen ◽  
...  
Keyword(s):  
Electric Field ◽  
Stark Effect ◽  
Comprehensive Evaluation ◽  
Critical Evaluation ◽  
Normal Modes ◽  
Mode Analysis ◽  
Local Mode ◽  
Underlying Assumption ◽  
Local Vibrational Mode ◽  
Internal Coordinates

Over the past two decades, the vibrational Stark effect has become an important tool to measure and analyze the in situ electric field strength in various chemical environments with infrared spectroscopy. The underlying assumption of this effect is that the normal stretching mode of a target bond such as CO or CN of a reporter molecule (termed vibrational Stark effect probe) is localized and free from mass-coupling from other internal coordinates, so that its frequency shift directly reflects the influence of the vicinal electric field. However, the validity of this essential assumption has never been assessed. Given the fact that normal modes are generally delocalized because of mass-coupling, this analysis was overdue. Therefore, we carried out a comprehensive evaluation of 68 vibrational Stark effect probes and candidates to quantify the degree to which their target normal vibration of probe bond stretching is decoupled from local vibrations driven by other internal coordinates. The unique tool we used is the local mode analysis originally introduced by Konkoli and Cremer, in particular the decomposition of normal modes into local mode contributions. Based on our results, we recommend 31 polyatomic molecules with localized target bonds as ideal vibrational Stark effect probe candidates.

scholarly journals Metal–Halogen Bonding Seen through the Eyes of Vibrational Spectroscopy

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 55 ◽  
Author(s):  
Vytor P. Oliveira ◽  
Bruna L. Marcial ◽  
Francisco B. C. Machado ◽  
Elfi Kraka
Keyword(s):  
Density Functional ◽  
Halogen Bonding ◽  
Fine Tuning ◽  
Mode Analysis ◽  
Planar Geometry ◽  
Local Mode ◽  
Special Role ◽  
Bonded Materials ◽  
Local Vibrational Mode ◽  
Donor And Acceptor

Incorporation of a metal center into halogen-bonded materials can efficiently fine-tune the strength of the halogen bonds and introduce new electronic functionalities. The metal atom can adopt two possible roles: serving as halogen acceptor or polarizing the halogen donor and acceptor groups. We investigated both scenarios for 23 metal–halogen dimers trans-M(Y2)(NC5H4X-3)2 with M = Pd(II), Pt(II); Y = F, Cl, Br; X = Cl, Br, I; and NC5H4X-3 = 3-halopyridine. As a new tool for the quantitative assessment of metal–halogen bonding, we introduced our local vibrational mode analysis, complemented by energy and electron density analyses and electrostatic potential studies at the density functional theory (DFT) and coupled-cluster single, double, and perturbative triple excitations (CCSD(T)) levels of theory. We could for the first time quantify the various attractive contacts and their contribution to the dimer stability and clarify the special role of halogen bonding in these systems. The largest contribution to the stability of the dimers is either due to halogen bonding or nonspecific interactions. Hydrogen bonding plays only a secondary role. The metal can only act as halogen acceptor when the monomer adopts a (quasi-)planar geometry. The best strategy to accomplish this is to substitute the halo-pyridine ring with a halo-diazole ring, which considerably strengthens halogen bonding. Our findings based on the local mode analysis provide a solid platform for fine-tuning of existing and for design of new metal–halogen-bonded materials.

scholarly journals Vibrational Analysis of Benziodoxoles and Benziodazolotetrazoles

Physchem ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 45-68
Author(s):  
Seth Yannacone ◽  
Kapil Dev Sayala ◽  
Marek Freindorf ◽  
Nicolay V. Tsarevsky ◽  
Elfi Kraka
Keyword(s):  
Energetic Materials ◽  
Substituent Effects ◽  
Vibrational Analysis ◽  
Mode Analysis ◽  
Hypervalent Iodine ◽  
Local Mode ◽  
Explosive Decomposition ◽  
Local Vibrational Mode ◽  
Bond Strengths ◽  
The Stability

Tetrazoles are well known for their high positive enthalpy of formation which makes them attractive as propellants, explosives, and energetic materials. As a step towards a deeper understanding of the stability of benziodazolotetrazole (BIAT)-based materials compared to their benziodoxole (BIO) counterparts, we investigated in this work electronic structure features and bonding properties of two monovalent iodine precursors: 2-iodobenzoic acid and 5-(2-iodophenyl)tetrazole and eight hypervalent iodine (III) compounds: I-hydroxybenzidoxolone, I-methoxybenziodoxolone, I-ethoxybenziodoxolone, I-iso-propoxybenziodoxolone and the corresponding I-hydroxyben ziodazolotetrazole, I-methoxybenziodazolotetrazole, I-ethoxybenziodazolotetrazole and I-iso- propoxybenziodazolotetrazole. As an efficient tool for the interpretation of the experimental IR spectra and for the quantitative assessment of the I−C, I−N, and I−O bond strengths in these compounds reflecting substituent effects, we used the local vibrational mode analysis, originally introduced by Konkoli and Cremer, complemented by electron density and natural bond orbital analyses. Based on the hypothesis that stronger bonds correlate with increased stability, we predict that, for both series, i.e., substituted benziodoxoles and benziodazolotetrazoles, the stability increases as follows: I-iso-propoxy < I-ethoxy < I-methoxy < I-hydroxy. In particular, the I−N bonds in the benziodazolotetrazoles could be identified as the so-called trigger bonds being responsible for the initiation of explosive decomposition in benziodazolotetrazoles. The new insight gained by this work will allow for the design of new benziodazolotetrazole materials with controlled performance or stability based on the modulation of the iodine bonds with its three ligands. The local mode analysis can serve as an effective tool to monitor the bond strengths, in particular to identify potential trigger bonds. We hope that this article will foster future collaboration between the experimental and computational community being engaged in vibrational spectroscopy.

The giant Stark effect in armchair-edge phosphorene nanoribbons under a transverse electric field

2018 ◽  
Vol 382 (4) ◽  
pp. 193-198 ◽  
Author(s):  
Benliang Zhou ◽  
Benhu Zhou ◽  
Pu Liu ◽  
Guanghui Zhou
Keyword(s):  
Electric Field ◽  
Stark Effect ◽  
Transverse Electric ◽  
Transverse Electric Field

High resolution spectroscopic study of H2 Se (40+,0) A1 and (40-,0) B2 stretching states: normal mode and local mode analysis

1997 ◽  
Vol 92 (6) ◽  
pp. 1073-1082 ◽  
Author(s):  
By ZE-YI ZHOU ◽  
XIAO-GANG WANG ◽  
ZHONG-PING ZHOU ◽  
OLEG N. ULENIKOV ◽  
GALINA A. ONOPENKO ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectroscopic Study ◽  
Normal Mode ◽  
Mode Analysis ◽  
Local Mode ◽  
Local Mode Analysis

scholarly journals Normal Mode Analysis as a Routine Part of a Structural Investigation

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3293 ◽  
Author(s):  
Jacob A. Bauer ◽  
Jelena Pavlović ◽  
Vladena Bauerová-Hlinková
Keyword(s):  
Normal Mode ◽  
Structural Study ◽  
Computer Technology ◽  
Structural Investigation ◽  
Normal Mode Analysis ◽  
Computational Cost ◽  
Normal Modes ◽  
Mode Analysis ◽  
Computationally Expensive ◽  
The Web

Normal mode analysis (NMA) is a technique that can be used to describe the flexible states accessible to a protein about an equilibrium position. These states have been shown repeatedly to have functional significance. NMA is probably the least computationally expensive method for studying the dynamics of macromolecules, and advances in computer technology and algorithms for calculating normal modes over the last 20 years have made it nearly trivial for all but the largest systems. Despite this, it is still uncommon for NMA to be used as a component of the analysis of a structural study. In this review, we will describe NMA, outline its advantages and limitations, explain what can and cannot be learned from it, and address some criticisms and concerns that have been voiced about it. We will then review the most commonly used techniques for reducing the computational cost of this method and identify the web services making use of these methods. We will illustrate several of their possible uses with recent examples from the literature. We conclude by recommending that NMA become one of the standard tools employed in any structural study.

Ein Level-Crossing-Experiment im angeregten (5p1/2 5d5/2)J=2-Term des Sn I zur Untersuchung der Energieverschiebungen im elektrischen Feld / Level-Crossing Experiment in the Excited (5p1/25d5/2)J=2-State of the Sn I for the Investigation of the Energy Shifts in an Electric Field

1970 ◽  
Vol 25 (5) ◽  
pp. 608-611
Author(s):  
P. Zimmermann
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Stark Effect ◽  
Second Order ◽  
Wave Functions ◽  
Zero Field ◽  
Homogeneous Electric Field ◽  
Level Crossing ◽  
Crossing Experiment ◽  
The Magnetic Field

Observing the change of the Hanle effect under the influence of a homogeneous electric field E the Stark effect of the (5p1/25d5/2)j=2-state in Sn I was studied. Due to the tensorial part β Jz2E2 in the Hamiltonian of the second order Stark effect the signal of the zero field crossing (M ∓ 2, M′ = 0 β ≷ 0 ) is shifted to the magnetic field H with gJμBH=2 | β | E2. From these shifts for different electric field strengths the value of the Stark parameter|β| = 0.21(2) MHz/(kV/cm)2 · gJ/1.13was deduced. A theoretical value of ß using Coulomb wave functions is discussed.

Single crystal polarized spectra in the near-infrared region: a local-mode analysis of the spectra of CsMnCl3•2X2O (X = H, D)

1994 ◽  
Vol 72 (5) ◽  
pp. 1211-1217 ◽  
Author(s):  
Ian M. Walker ◽  
Paul J. McCarthy
Keyword(s):  
Hydrogen Bond ◽  
Near Infrared ◽  
Infrared Region ◽  
Chloride Ions ◽  
Mode Analysis ◽  
Local Mode ◽  
Local Modes ◽  
Near Infrared Spectra ◽  
Parameter Values ◽  
Local Mode Analysis

Polarized near-infrared spectra of single crystals of CsMnCl3•2X2O (X = H, D) were recorded at 10 K. Those bands which could be assigned to O—H or O—D stretch overtones were analyzed using local-mode theory specifically adapted for systems having less than C2v symmetry. Both O—H oscillators form nearly linear hydrogen bonds to neighboring chloride ions at different distances. As a result, the local-mode harmonic frequency and anharmonicity parameters show characteristic shifts from their gas-phase values. The parameter values cover an unusually narrow range in this crystal, considering the spread in hydrogen-bond distances. Assignment of stretch overtone bands to specific oscillators in the crystal was made by using the polarization behavior expected of local modes in the oriented gas model. Several of the overtone bands show combinations with lattice modes or low-energy hydrogen-bond modes in unusual detail.

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