Calculation of structures and vibrational spectra of acetonitrile clusters

Siebers, J. G.; Buck, U.; Beu, Titus A.

doi:10.1016/s0301-0104(98)00300-0

Cited by 28 publications

(42 citation statements)

References 31 publications

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“…As can be seen, the overall agreement of all theoretical methods with the experimental data is very good. The QCISD and CCD levels of theory overestimate the dipole moment of isolated CH 3 CN (the experimental value is 3.92 D 64–66), while all of the density functional levels underestimate this quantity. Basically, acetonitrile interacts with alkaline metal cations through the nitrogen atom.…”

Section: Resultsmentioning

confidence: 82%

Interaction of acetonitrile with alkaline metal cations: A density functional, coupled‐cluster, and quadratic configuration interaction study

Pejov

2001

Int J of Quantum Chemistry

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ABSTRACT:A systematic quantum chemical study of CH 3 CN and its CH 3 CN· · ·M + 1:1 model adducts (M + ∈ {Li + , Na + }) is presented, with respect to binding energetics, structural and vibrational force field changes. Several gradient-corrected density functional levels of theory were employed (of both "pure" and "hybrid" character), together with the coupled cluster including double substitutions from the Hartree-Fock determinant (CCD) and quadratic configuration interaction including single and double substitutions (QCISD) methods [with the rather large 6-311G(d,p) basis set], and their performances compared. The binding energy decompositions according to the Kitaura-Morokuma scheme and the reduced variational space self-consistent field (RVS-SCF) method have shown that the electrostatic plus polarization interaction terms are primarily responsible for overall stabilization, while the charge-transfer term is negligibly small and virtually identical for both adducts. The computed harmonic vibrational frequencies for acetonitrile correlate excellently with the experimental ones (r 2 > 0.9998 for almost all cases, while for the BLYP level, r 2 = 1). It is shown for the first time that the experimentally observed blue shifts of the ν CN mode are caused even by formation of 1:1 adducts, contrary to the previously accepted opinions. The CCD and QCISD, as well as the BPW91 and BP86 levels of theory predict almost excellently the ν CN mode blue shift upon adduct formation, while the BLYP and B3LYP levels perform significantly poorer.

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Section: Resultsmentioning

confidence: 82%

Interaction of acetonitrile with alkaline metal cations: A density functional, coupled‐cluster, and quadratic configuration interaction study

Pejov

2001

Int J of Quantum Chemistry

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“…Inspection of these structures reveals that in the PP(AN) 4 cluster the structure of the (AN) 4 fragment is practically the same as that of an isolated cluster of four AN molecules. 35 This reflects the fact that the bonding between two AN molecules is stronger than the AN-PP bond, probably because of a strong dipoledipole interaction. In sharp contrast, the structure of the PBN-(AN) 4 cluster is completely different: there is no similarity between the (AN) 4 fragment and an isolated one.…”

Section: Iv4 Different Emission Properties Of An Clusters Of Pp Andmentioning

confidence: 99%

Charge-Transfer-Type Fluorescence of 4-(1H-Pyrrol-1-yl)benzonitrile (PBN) and N-Phenylpyrrole (PP) in Cryogenic Matrixes: Evidence for Direct Excitation of the CT Band

et al. 2005

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The fluorescence spectrum of PBN in a neat argon matrix is excitation-wavelength-dependent: at short excitation wavelengths, it consists of dual emission assigned to a charge-transfer (CT) state and a much weaker band assigned to the locally excited (LE) state. The CT emission is broad and almost completely devoid of vibrational structure, whereas the LE band is characterized by vibrationally resolved emission. At long excitation wavelengths, only CT emission is observed, indicating that the CT state is populated directly by light absorption and not via the LE state. Comparison with jet-cooled spectra of the bare molecule allows the unambiguous assignment of the LE spectrum and the location of the 0,0 band. The matrix LE emission spectrum is blue-shifted with respect to that of the gas phase, showing that the dipole moment of the LE state is smaller than that of the ground state. The fluorescence spectrum of PBN in an argon matrix does not change appreciably when acetonitrile (AN) is added to the matrix, in contrast to the case of N-phenylpyrrol (PP) (Schweke, D.; Haas, Y. J. Phys. Chem. A 2003, 107, 9554), for which addition of AN results in the appearance of two well separated emission bands. The different photophysical behaviors of PP and PBN in an argon matrix (and in supersonic jets) are analyzed by a simple model that considers the restriction of large-amplitude motions in the matrix. The implications of these low-temperature studies for understanding the properties of these systems in liquid solution are discussed.

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“…The acetonitrile dimer has been the subject of a variety of previous studies, both theoretical 13–22 and experimental 23–35. The computational studies have used a number of theoretical models, varying from complete neglect of differential overlap (CNDO)/force 14, through restricted Hartree–Fock 13, 15, 16, 18, 19, 21, 22 and density functional theory (B3LYP) 22 to second‐ and fourth‐order Møller–Plesset perturbation theory (MP2 16–22 and MP4 22), and with basis sets ranging in size from 3‐21G 15, 16 to 6‐311++G(2d,2p) 22. Most reports agree that the most stable dimer is an antiparallel one of C 2h symmetry, with one CH bond of each monomer molecule lying in the symmetry plane 13, 15–17, 19–22, forming a CHN hydrogen bond, although an alternative C 2h structure, with two bifurcated CHN hydrogen bonds, has been favored in some reports 14, 18.…”

Section: Introductionmentioning

confidence: 99%

“…Collinear dimers of C 3v symmetry, with the two methyl groups either eclipsed or staggered, have also been examined 13, 14, 19, 21. Most studies place the interaction energy of the most stable structure in the region of about −20 kJ mol −1 14, 15, 17–22. Mathieu et al 15, 16 reported the computed wavenumbers and their complex–monomer shifts, while Siebers and co‐workers 20 calculated the shifts for the CH 3 rocking and the CC stretching modes only.…”

Section: Introductionmentioning

confidence: 99%

Ab initio calculations of the structural, energetic, and vibrational properties of some hydrogen bonded and van der Waals dimers. Part 4. The acetonitrile dimer

Ford

Glasser

2001

Int J of Quantum Chemistry

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ABSTRACT:The structures, interaction energies, Mulliken atomic charges, and vibrational spectra of five dimers of acetonitrile, CH 3 CN, have been determined by means of ab initio molecular orbital theory, at the second order level of Møller-Plesset perturbation theory, using the 6-31++G(d,p) split-valence polarized basis set, augmented with diffuse functions. The structural features of the dimers are discussed, as well as their respective interaction energies, which have been corrected for basis set superposition error by the full counterpoise technique of Boys and Bernardi. The atomic charge reorganizations resulting from dimerization have also been discussed. The vibrational wavenumbers and infrared intensities of each dimer have been computed and, in the case of the most probable dimer, they have been used to determine the wavenumber shifts relative to the corresponding modes of the monomer. The shifts have been compared with those in the infrared and Raman spectra of acetonitrile molecules trapped in cryogenic matrices, previously reported in the literature. The computed and experimental results support the conclusion that the favored dimer structure is a centrosymmetric cyclic species of C 2h symmetry, stabilized by two weak CH· · ·N hydrogen bonds.

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Calculation of structures and vibrational spectra of acetonitrile clusters

Cited by 28 publications

References 31 publications

Interaction of acetonitrile with alkaline metal cations: A density functional, coupled‐cluster, and quadratic configuration interaction study

Interaction of acetonitrile with alkaline metal cations: A density functional, coupled‐cluster, and quadratic configuration interaction study

Charge-Transfer-Type Fluorescence of 4-(1H-Pyrrol-1-yl)benzonitrile (PBN) and N-Phenylpyrrole (PP) in Cryogenic Matrixes: Evidence for Direct Excitation of the CT Band

Ab initio calculations of the structural, energetic, and vibrational properties of some hydrogen bonded and van der Waals dimers. Part 4. The acetonitrile dimer

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