Near-infrared spectra and rovibrational dynamics on a four-dimensional <i>ab initio</i> potential energy surface of (HBr)2

Castillo-Chará, Jairo; McIntosh, Avery L.; Wang, Z.; Lucchese, Robert R.; Bevan, J. W.

doi:10.1063/1.1736632

Cited by 18 publications

(22 citation statements)

References 55 publications

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“…46,47 R is the distance between the centers of mass of the two monomers, the angles 1 and 2 describe the orientation of the monomers CO and HI, respectively, and the dihedral angle describes the relative internal orientation of both monomers. 3͒.…”

Section: Ab Initio Calculation Of the Intermolecular Potentialmentioning

confidence: 99%

“…In order to generate a global representation of the potential energy surface ͑PES͒, the calculated 274 ab initio points at each value of R j were fitted to the spherical expansion 46,47 …”

Section: Fitting Of the Ab Initio Potentialmentioning

confidence: 99%

“…͑2͒, the P L ͉M͉ ͑cos ͒ are the associated Legendre polynomials, and the symbol ͗L 1 , M ; L 2 ,-M ͉ L ,0͘ is the Clebsch-Gordan coefficient. 46,47 46 A weighting factor F w =75 cm −1 is used in order to have an absolute average difference less than 6 cm −1 between the values of the points in the ab initio and fitted potentials, for the points within 250 cm −1 of the minimum of the potential.…”

Section: Fitting Of the Ab Initio Potentialmentioning

confidence: 99%

“…46,47 For the kinetic energy expression in each of the calculations, the experimental B 0 rotational constants for the isolated monomers 54,55 were used. The rovibrational energy levels for the 4D PES were calculated by the pseudospectral approach, discussed previously.…”

Section: Calculation Of Rovibrational Energy Levelsmentioning

confidence: 99%

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A ground state morphed intermolecular potential for the hydrogen bonded and van der Waals isomers in OC:HI and a prediction of an anomalous deuterium isotope effect

Rivera‐Rivera

Wang

McElmurry

et al. 2010

The Journal of Chemical Physics

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An extended analysis of the noncovalent interaction OC:HI is reported using microwave and infrared supersonic jet spectroscopic techniques. All available spectroscopic data then provide the basis for generating an accurately determined vibrationally complete semiempirical intermolecular potential function using a four-dimensional potential coordinate morphing methodology. These results are consistent with the existence of four bound isomers: OC-HI, OC-IH, CO-HI, and CO-IH. Analysis also leads to unequivocal characterization of the common isotopic ground state as having the OC-HI structure and with the first excited state having the OC-IH structure with an energy of 3.4683(80) cm(-1) above the ground state. The potential is consistent with the following barriers between the pairs of isomers: 382(4) cm(-1) (OC-IH/OC-HI), 294(5) cm(-1) (CO-IH/CO-HI), 324(3) cm(-1) (OC-IH/CO-IH), and 301(2) cm(-1) (OC-HI/CO-HI) defined with respect to each lower minimum. The potential is also determined to have a linear OC-IH van der Waals global equilibrium minimum structure having R(e)=4.180(11) Å, θ(1)=0.00(1)°, and θ(2)=0.00(1)°. This is differentiated from its OC-HI ground state hydrogen bound structure having R(0)=4.895(1) Å, θ(1)=20.48(1)°, and θ(2)=155.213(1)° where the distances are defined between the centers of mass of the monomers and θ(1) and θ(2) as cos(-1)[(1/2)] for i=1 and 2. A fundamentally new molecular phenomenon - ground state isotopic isomerization is proposed based on the generated semiempirical potential. The protonated ground state hydrogen-bonded OC-HI structure is predicted to be converted on deuteration to the corresponding ground state van der Waals OC-ID isomeric structure. This results in a large anomalous isotope effect in which the R(0) center of mass distance between monomeric components changes from 4.895(1) to 4.286(1) Å. Such a proposed isotopic effect is demonstrated to be a consequence of differential zero point energy factors resulting from the shallower nature of hydrogen bonding at a local potential minimum (greater quartic character of the potential) relative to the corresponding van der Waals global minimum. Further consequences of this anomalous deuterium isotope effect are also discussed.

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Section: Ab Initio Calculation Of the Intermolecular Potentialmentioning

confidence: 99%

Section: Fitting Of the Ab Initio Potentialmentioning

confidence: 99%

Section: Fitting Of the Ab Initio Potentialmentioning

confidence: 99%

Section: Calculation Of Rovibrational Energy Levelsmentioning

confidence: 99%

See 2 more Smart Citations

A ground state morphed intermolecular potential for the hydrogen bonded and van der Waals isomers in OC:HI and a prediction of an anomalous deuterium isotope effect

Rivera‐Rivera

Wang

McElmurry

et al. 2010

The Journal of Chemical Physics

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“…[23][24][25][26][27] In contrast to rare-gas matrices, halogens trapped in solid pH 2 can react with the matrix itself. Concerning the hydrogen halogen H 2 X 2 systems, with X = F, Cl, and Br, the ab initio interactions of the (HX) 2 dimers [28][29][30][31][32] and of the atom-molecule pairs X-H 2 [33][34][35][36] have been studied in view of hydrogen bonding and the hydrogen halogen reaction. However, with the exceptions of H 2 -I 2 37, 38 and H 2 -F 2 , 39 no reports about pair potentials for the H 2 -X 2 dimers could be found in the literature.…”

Section: Introductionmentioning

confidence: 99%

Rotationally adiabatic pair interactions of para- and ortho-hydrogen with the halogen molecules F2, Cl2, and Br2

Berg

Accardi

Paulus

et al. 2014

The Journal of Chemical Physics

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The present work is concerned with the weak interactions between hydrogen and halogen molecules, i.e., the interactions of pairs H2-X2 with X = F, Cl, Br, which are dominated by dispersion and quadrupole-quadrupole forces. The global minimum of the four-dimensional (4D) coupled cluster with singles and doubles and perturbative triples (CCSD(T)) pair potentials is always a T shaped structure where H2 acts as the hat of the T, with well depths (De) of 1.3, 2.4, and 3.1 kJ/mol for F2, Cl2, and Br2, respectively. MP2/AVQZ results, in reasonable agreement with CCSD(T) results extrapolated to the basis set limit, are used for detailed scans of the potentials. Due to the large difference in the rotational constants of the monomers, in the adiabatic approximation, one can solve the rotational Schrödinger equation for H2 in the potential of the X2 molecule. This yields effective two-dimensional rotationally adiabatic potential energy surfaces where pH2 and oH2 are point-like particles. These potentials for the H2-X2 complexes have global and local minima for effective linear and T-shaped complexes, respectively, which are separated by 0.4-1.0 kJ/mol, where oH2 binds stronger than pH2 to X2, due to higher alignment to minima structures of the 4D-pair potential. Further, we provide fits of an analytical function to the rotationally adiabatic potentials.

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High‐ResolutionFTIRand Diode Laser Spectroscopy of Supersonic Jets

Snels

Horká‐Zelenková

Hollenstein

et al. 2011

Handbook of High‐resolution Spectroscopy

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Fourier transform infrared (FTIR) spectrometers and tunable diode lasers in combination with a supersonic molecular beam expansion are a perfect tool for the investigation of molecules, ions, and radicals at low temperatures. The internal degrees of freedom of the molecules are adiabatically cooled to very low temperatures and thus only low-lying energy levels are populated. The reduction of the number of populated levels at low temperatures makes the assignment of the spectra much easier as compared to the congested room-temperature spectra. Under certain conditions, the Doppler linewidths are greatly reduced, corresponding to very low effective translational temperatures. Supersonic expansion also provides a suitable method for producing and investigating van der Waals clusters and hydrogen-bonded complexes. Unstable species such as radicals and ions can be efficiently produced and studied in a molecular beam. The low rotational temperature allows for the study of nuclear spin symmetry conservation or conversion between nuclear spin isomers. A molecular beam expansion can be obtained by expanding gas through a slit or a circular nozzle. Both expansion geometries can be used in combination with a multipass optical setup and with cavity ring down spectroscopy, which enhances the effective absorption path length. Cooling of the molecules can be promoted by seeding in noble gases. This article summarizes the general aspects of the experimental technique as well as current developments. To demonstrate how powerful the combination of a molecular beam expansion with tunable diode laser and FTIR spectroscopy can be, we report results on some important current examples.

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Near-infrared spectra and rovibrational dynamics on a four-dimensional ab initio potential energy surface of (HBr)2

Cited by 18 publications

References 55 publications

A ground state morphed intermolecular potential for the hydrogen bonded and van der Waals isomers in OC:HI and a prediction of an anomalous deuterium isotope effect

A ground state morphed intermolecular potential for the hydrogen bonded and van der Waals isomers in OC:HI and a prediction of an anomalous deuterium isotope effect

Rotationally adiabatic pair interactions of para- and ortho-hydrogen with the halogen molecules F2, Cl2, and Br2

High‐ResolutionFTIRand Diode Laser Spectroscopy of Supersonic Jets

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