Frequencies and absorption intensities of fundamentals and overtones of NH stretching vibrations of pyrrole and pyrrole–pyridine complex studied by near-infrared/infrared spectroscopy and density-functional-theory calculations

Futami, Yoshisuke; Ozaki, Yasushi; Hamada, Yoshiaki; Wójcik, Marek J.; Ozaki, Yukihiro

doi:10.1016/j.cplett.2009.09.063

Cited by 45 publications

(56 citation statements)

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“…Due to the high anharmonicity of this mode, accurate theoretical methods as discussed in this section are essential. This was demonstrated by Futami et al on the example of the pyrrole, pyridine, and pyrrole–pyridine complexes (Futami et al, 2009). The experimental observation of non-bonded pyrrole reveals a well-resolved 2νNH peak at 6,856 cm −1 ; yet, the band is absent in the pyrrole–pyridine complex.…”

Section: Theoretical Near-infrared Spectroscopy–an Overview Of the Emmentioning

confidence: 78%

“…The experimental observation of non-bonded pyrrole reveals a well-resolved 2νNH peak at 6,856 cm −1 ; yet, the band is absent in the pyrrole–pyridine complex. A computational study explained that, in the complex the transition dipole moment is remarkably reduced for the first overtone mode of the hydrogen-bonded NH group (Futami et al, 2009). Continued further by Futami et al, other complexes featuring NH…π hydrogen bonding, e.g., pyrol-ethylene and pyrrole-acetylene systems, were evidenced to follow the above pattern (Futami et al, 2014).…”

Section: Theoretical Near-infrared Spectroscopy–an Overview Of the Emmentioning

confidence: 99%

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Breakthrough Potential in Near-Infrared Spectroscopy: Spectra Simulation. A Review of Recent Developments

2019

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Near-infrared (12,500–4,000 cm −1 ; 800–2,500 nm) spectroscopy is the hallmark for one of the most rapidly advancing analytical techniques over the last few decades. Although it is mainly recognized as an analytical tool, near-infrared spectroscopy has also contributed significantly to physical chemistry, e.g., by delivering invaluable data on the anharmonic nature of molecular vibrations or peculiarities of intermolecular interactions. In all these contexts, a major barrier in the form of an intrinsic complexity of near-infrared spectra has been encountered. A large number of overlapping vibrational contributions influenced by anharmonic effects create complex patterns of spectral dependencies, in many cases hindering our comprehension of near-infrared spectra. Quantum mechanical calculations commonly serve as a major support to infrared and Raman studies; conversely, near-infrared spectroscopy has long been hindered in this regard due to practical limitations. Advances in anharmonic theories in hyphenation with ever-growing computer technology have enabled feasible theoretical near-infrared spectroscopy in recent times. Accordingly, a growing number of quantum mechanical investigations aimed at near-infrared region has been witnessed. The present review article summarizes these most recent accomplishments in the emerging field. Applications of generalized approaches, such as vibrational self-consistent field and vibrational second order perturbation theories as well as their derivatives, and dense grid-based studies of vibrational potential, are overviewed. Basic and applied studies are discussed, with special attention paid to the ones which aim at improving analytical spectroscopy. A remarkable potential arises from the growing applicability of anharmonic computations to solving the problems which arise in both basic and analytical near-infrared spectroscopy. This review highlights an increased value of quantum mechanical calculations to near-infrared spectroscopy in relation to other kinds of vibrational spectroscopy.

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Section: Theoretical Near-infrared Spectroscopy–an Overview Of the Emmentioning

confidence: 78%

Section: Theoretical Near-infrared Spectroscopy–an Overview Of the Emmentioning

confidence: 99%

Breakthrough Potential in Near-Infrared Spectroscopy: Spectra Simulation. A Review of Recent Developments

2019

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“…84 One good thing is rapid progress of quantum chemical calculations of overtones. [26][27][28] We suppose that quantum chemical calculations play very important roles in spectral analysis and investigations in NIR spectroscopy.…”

Section: Future Prospectsmentioning

confidence: 99%

“…Moreover, recently, quantum chemical calculations, such as density function theory (DFT) calculations, are becoming popular, even in NIR spectral analysis. [26][27][28] One can calculate the intensities and frequencies of overtones bands using quantum chemistry calculations.…”

Section: -10mentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10] Recent rapid developments of NIR spectrometers, particularly FT-NIR spectrometers, and spectral-analysis methods, like chemometrics, [16][17][18][19][20] two-dimensional correlation analysis, 24,25 and quantum chemical calculations, [26][27][28] have stimulated novel studies on the overtones and combination modes, as well as their anharmonicities and molecular structure and interactions. [1][2][3][4][5] For the last five to ten years, much attention has been paid to NIR imaging, portable and hand-held spectrometers, on-line monitoring, PAT (process analysis technology), and medical diagnosis.…”

Section: ·1 Brief History Of Nir Spectroscopymentioning

confidence: 99%

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