Calculation of the vibronic structure of the photodetachment spectra of CCCl− and CCBr−

Mishra, Sabyashachi; Vallet, Valérie; Poluyanov, Leonid V.; Domcke, Wolfgang

doi:10.1063/1.2363193

Cited by 9 publications

(4 citation statements)

References 61 publications

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“…The SERS spectral peaks coincided with solid intrinsic spectrum of γ-666 (see the bottom curve in Figure 10 a). One of the main characteristic peaks at 345 cm −1 is ascribed to the stretching vibration of C−Cl in γ-666, and the bands in the region of 400–1400 cm −1 stand for C−C and C−H stretching, and CH 2 bending from the aliphatic cyclic structure of the analyzed molecules [ 54 , 55 , 56 ].…”

Section: Resultsmentioning

confidence: 99%

Kinetically-Controlled Growth of Chestnut-Like Au Nanocrystals with High-Density Tips and Their High SERS Performances on Organochlorine Pesticides

et al. 2018

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A modified seed growth route was developed to fabricate the Au nanocrystals with high-density tips based on kinetically-controlled growth via adjusting the adding rate of Au seeds into growth solution. The obtained Au nanostructures were chestnut-like in morphology and about 100 nm in size. They were built of the radial [111]-oriented nanoneedles and were 30–50 nm in length. There were about 120–150 tips in each nanocrystal. The formation of chestnut-like Au nanocrystals is ascribed to surfactant-induced preferential growth of seeds along direction [111]. Importantly, the chestnut-like Au configuration displayed powerful surface enhanced Raman scattering (SERS) performance (enhance factor > 107), owing to the high density of tips. Further, such film was used as a SERS substrate for the detection of lindane (γ-666) molecules (the typical organochlorine pesticide). The detection limit was about 10 ppb, and the relationship between SERS intensity I and concentration C of 666 accords with the double logarithm linear. This work presents a simple approach to Au nanocrystal with high-density tips, and provides a highly efficacious SERS-substrate for quantitative and trace recognition of toxic chlorinated pesticides.

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Section: Resultsmentioning

confidence: 99%

Kinetically-Controlled Growth of Chestnut-Like Au Nanocrystals with High-Density Tips and Their High SERS Performances on Organochlorine Pesticides

et al. 2018

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“…The Raman spectra of the solid state of aldrin, α-endosulfane, lindane, and dieldrin are shown in Figure . The tentative assignment of the vibrational bands of the studied pesticides was made on the basis of the data found in the literature. , Briefly, the Raman spectra are dominated by a group of bands appearing in the 300–400 cm –1 region, attributed to C–Cl stretching vibrations (ν(CCl)) (Figure ). These bands are the most intense in the Raman spectra, since the C–Cl stretching induces a large variation of the polarizability of the analyzed molecules.…”

Section: Resultsmentioning

confidence: 99%

Sensitive Surface-Enhanced Raman Spectroscopy (SERS) Detection of Organochlorine Pesticides by Alkyl Dithiol-Functionalized Metal Nanoparticles-Induced Plasmonic Hot Spots

et al. 2014

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In this work, we report the detection of the organochlorine pesticides aldrin, dieldrin, lindane, and α-endosulfan by using surface-enhanced Raman spectroscopy (SERS) and optimization of the SERS-sensing substrate. In order to overcome the inherent problem of the low affinity of the above pesticides, we have developed a strategy consisting of functionalization of the metal surface with alkyl dithiols in order to achieve two different goals: (i) to induce the nanoparticle linkage and create interparticle junctions where sensitive hot spots needed for SERS enhancement are present, and (ii) to create a specific environment in the nanogaps between silver and gold nanoparticles, making them suitable for the assembly and SERS detection of the analyzed pesticides. Afterward, an optimization of the sensing substrate was performed by varying the experimental conditions: type of metal nanoparticles, molecular linker (aromatic versus aliphatic dithiols and the length of the intermediate chain), surface coverage, laser excitation wavelength. From the adsorption isotherms, it was possible to deduce the corresponding adsorption constant and the limit of detection. The present results confirm the high sensitivity of SERS for the detection of the organochlorine pesticides with a limit of detection reaching 10(-8) M, thus providing a solid basis for the construction of suitable nanosensors for the identification and quantitative analysis of this type of chemical.

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“…At first, we focus on the spin-orbit split 2 [17,18] and their results are compared to ours obtained by the vibronic coupling model in the fourcomponent framework. A possible / coupling is neglected in our first investigation, but it can be included by extending the space of interacting electronic states (see, for example, [19][20][21] where this type of coupling is described in the standard approach). The energies of the cationic and states also depend on the stretching modes ν 1 and ν 3 leading to a problem of higher dimensionality as studied by Biczysko and Tarroni [22].…”

Section: Introductionmentioning

confidence: 99%

A four-component quadratic vibronic coupling approach to the Renner–Teller effect in linear triatomic molecules. The $^2\Pi _\frac{1}{2}$, $^2\Pi _\frac{3}{2}$ manifold of BrCN⁺and ClCN⁺

Pernpointner

Salopiata

2013

J. Phys. B: At. Mol. Opt. Phys.

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In this work, we present the four-component quadratic vibronic coupling model for the description of the Renner–Teller effect (RTE) in the presence of the spin–orbit coupling. The interaction of the two potential energy surfaces emerging from the cationic 2Π states of singly ionized linear triatomic molecules is described by the quadratic coupling constant c for the genuine RT repulsion and the second parameter, d, for a nonconstant spin–orbit coupling varying with the bond angle of the triatomic. The emergence of a linear RT constant in the presence of the spin–orbit operator was originally shown by Poluyanov and Domcke (2004 Chem. Phys. 301 111–27) and is based on the application of the Breit–Pauli Hamiltonian in combination with nonrelativistic wavefunctions. In contrast to this methodology, we generate the diabatic RT Hamiltonian in a 4-spinor basis where the symmetry transformation properties of the electronic and vibrational wavefunctions completely determine the RT matrix structure. Explicit access to highly correlated wavefunctions is not required in our approach. In addition, the four-component vibronic coupling model takes into account the full spatial orbital relaxation upon the inclusion of the spin–orbit coupling and is therefore well suited for heavy systems. The third parameter, p, accounting for a possible pseudo-Jahn–Teller interaction is not considered here, but it does not introduce a principal difficulty. As the initial systems for this study, we considered the BrCN+ and ClCN+ cations and determined the c and d parameters by a numerical fit to accurate adiabatic potential energy surfaces obtained by the relativistic Fock-space coupled-cluster method. New values for the computed linear RT parameter d amount to 14.7 ± 0.5 cm−1 for ClCN+ and 73.2 ± 0.7 cm−1 for BrCN+.

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Calculation of the vibronic structure of the photodetachment spectra of CCCl− and CCBr−

Cited by 9 publications

References 61 publications

Kinetically-Controlled Growth of Chestnut-Like Au Nanocrystals with High-Density Tips and Their High SERS Performances on Organochlorine Pesticides

Kinetically-Controlled Growth of Chestnut-Like Au Nanocrystals with High-Density Tips and Their High SERS Performances on Organochlorine Pesticides

Sensitive Surface-Enhanced Raman Spectroscopy (SERS) Detection of Organochlorine Pesticides by Alkyl Dithiol-Functionalized Metal Nanoparticles-Induced Plasmonic Hot Spots

A four-component quadratic vibronic coupling approach to the Renner–Teller effect in linear triatomic molecules. The $^2\Pi _\frac{1}{2}$, $^2\Pi _\frac{3}{2}$ manifold of BrCN⁺and ClCN⁺

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Calculation of the vibronic structure of the photodetachment spectra of CCCl− and CCBr−

Cited by 9 publications

References 61 publications

Kinetically-Controlled Growth of Chestnut-Like Au Nanocrystals with High-Density Tips and Their High SERS Performances on Organochlorine Pesticides

Kinetically-Controlled Growth of Chestnut-Like Au Nanocrystals with High-Density Tips and Their High SERS Performances on Organochlorine Pesticides

Sensitive Surface-Enhanced Raman Spectroscopy (SERS) Detection of Organochlorine Pesticides by Alkyl Dithiol-Functionalized Metal Nanoparticles-Induced Plasmonic Hot Spots

A four-component quadratic vibronic coupling approach to the Renner–Teller effect in linear triatomic molecules. The $^2\Pi _\frac{1}{2}$, $^2\Pi _\frac{3}{2}$ manifold of BrCN+and ClCN+

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A four-component quadratic vibronic coupling approach to the Renner–Teller effect in linear triatomic molecules. The $^2\Pi _\frac{1}{2}$, $^2\Pi _\frac{3}{2}$ manifold of BrCN⁺and ClCN⁺