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A C Legon - One of the best experts on this subject based on the ideXlab platform.
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nuclear hyperfine coupling Constants of aluminium monoiodide determined by fourier transform microwave spectroscopy
Chemical Physics Letters, 2006Co-Authors: Nicholas R Walker, Simon G Francis, Joshua J Rowlands, A C LegonAbstract:Abstract The ground-state Rotational spectrum of 27 Al 127 I has been investigated by Fourier-transform microwave spectroscopy. AlI was generated by reaction of laser-ablated aluminium vapour with methyl iodide. The Rotational Constant ( B 0 ), nuclear quadrupole coupling Constants ( χ aa Al , χ aa I ) and the nuclear spin-rotation Constant of iodine ( C bb I ) have been re-determined with high precision. The nuclear spin-rotation Constant of aluminium ( C bb Al ) , the nuclear spin–spin Constants ( D aa Al , I , δ Al , I ) and the dependence of the coupling Constant χ aa I on J ( χ J I ) were determined. D aa Al , I and δ Al,I agree with calculated values and χ J I is consistent in sign and magnitude with the known dependence of χ aa I on vibrational state.
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inter and intramolecular electron transfer on formation of 15n2 brcl determined from halogen nuclear quadrupole coupling in the Rotational spectrum
Physical Chemistry Chemical Physics, 2002Co-Authors: A C Legon, P OttavianiAbstract:The ground-state Rotational spectra of the four isotopomers 15N2⋯79Br35Cl, 15N2⋯81Br35Cl, 15N2⋯79Br37Cl and 15N2⋯81Br37Cl of a complex formed between 15N2 and bromine monochloride were observed by pulsed-jet, Fourier-transform microwave spectroscopy. Observed spectra were characteristic of a linear or quasi-linear molecule, with Br involved in the weak interaction, and were analysed to give the Rotational Constant B0, the centrifugal distortion Constant DJ, the nuclear quadrupole coupling Constants χaa(X) (X=Br or Cl) and the Br spin–rotation coupling Constant Mbb(Br) for each isotopomer. Interpretation of χaa(X) values showed that the intermolecular electron transfer δ(Ni→Br)e on complex formation is negligible while its intramolecular counterpart δ(Br→Cl)e=0.012(2) e is also small. The electronic redistribution is consistent with a weak interaction of N2 and BrCl, as confirmed by the intermolecular stretching force Constant kσ=4.40(2) N m−1. Values of r(N⋯Br), δ(Ni→Br)e, δ(Br→Cl)e, and kσ for 15N2⋯BrCl are compared with those for HCN⋯BrCl and H3N⋯BrCl, all of which involve weak binding of N to Br.
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the Rotational Constant a0 and planarity of the hydrogen bonded complex h2co hcl
Journal of the Chemical Society Faraday Transactions, 1996Co-Authors: A C LegonAbstract:A fit of µa, R-branch transitions of the nearly prolate asymmetric rotor H2CO⋯HCl (κ≈–0.99) demonstrated that even a relatively large A0 Rotational Constant can be determined with useful accuracy from such a limited set of data, provided the frequencies are of sufficient accuracy. Thus the set of spectroscopic Constants A0, B0, C0, ΔJ, ΔJK, δJ, χaa, (χbb–χcc), χab and ½{Mbb+Mcc} are reported for H2CO⋯H35Cl. The subsequent observation of two µb, R-branch transitions led to a much more accurate value of A0, but this did not lie outside the error of the preliminary value, confirming the usefulness of the initial approach. The inertial defect Δ0= 0.5724(1) u A2 demonstrates that the nuclei in H2CO⋯H35Cl are copolanar. Fits of limited numbers of µa, R-branch transition frequencies for each of H2CO⋯H37Cl, D2CO⋯H35Cl and D2CO⋯H37Cl led to Δ0 values for the isotopomers identical within experimental error to that of H2CO⋯H35Cl.
Takehiko Tanaka - One of the best experts on this subject based on the ideXlab platform.
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high resolution fourier transform emission spectroscopy of the a 2πi x 2πi band of the ocs ion
Journal of Chemical Physics, 2017Co-Authors: Kensuke Harada, Keiichi Tanaka, Yoshihiro Nakashima, Takehiko TanakaAbstract:High resolution Fourier transform emission spectroscopy of the A∼2Πi–X∼2Πi band of the OCS+ ion was performed in the UV region to observe the ν1 (CO stretch) progression bands (υ1 = 0 → 2–5) for both the Ω=3/2 and 1/2 spin components. Accurate molecular Constants including the Rotational Constants, B0 = 0.194 765(13) and 0.187 106(13) cm−1, and the spin-orbit interaction Constants, A0 = −381.0(56) and −126.5(56) cm−1, were determined for the X∼2Π and A∼2Π states, respectively, by the simultaneous analysis of the observed progression bands. The CO bond length (rCO = 1.2810 A) for the A∼2Π state, derived from the Rotational Constant B0 and Franck-Condon factors, is longer by 0.1756 A than that (1.1054 A) for the X∼2Π state, while the CS bond length for the A∼2Π state is shorter by 0.0905 A than that for the X∼2Π state. Pure Rotational transition frequencies in the ground X∼2Π state are predicted, as well as transition frequencies of the ν1 fundamental band, with the present molecular Constants.
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CO2 laser Stark spectroscopy of the ν4 band of SiHF3: The C0 Rotational Constant and vibrationally induced dipole moment
Journal of Chemical Physics, 1992Co-Authors: Kensuke Harada, Syuji Akao, Kazumi Miyachi, Keiichi Tanaka, Takehiko TanakaAbstract:The ν4 (SiF3 degenerate stretch) fundamental band of SiHF3 has been investigated by the CO2 laser Stark spectroscopy. The vibrationally induced dipole moment was found to give remarkable perturbations of the type (Δl,ΔK)=(2,−1) in the ν4 vibrational state under intense electric field. Several perturbation‐induced rovibrational transitions obeying the Δ(K−l)=±3 selection rules were observed in the Stark spectrum. The C0 Rotational Constant, which is otherwise hard to obtain for a symmetric top molecule, was determined to be 4134.73(71) MHz. The vibrationally induced dipole moment μr in the ν4 state was derived as ±0.034 38(17) D, the sign being experimentally indeterminable. The band origin, the Coriolis Constant Cζ4, and the vibration–rotation Constant αC4 are 999.581 076(30) cm−1, 2445.59(71) MHz, and 9.243(22) MHz, respectively. The dipole moment is 1.359 20(22) D in the ground state, and increases by 0.026 73(10) D on excitation of the ν4 vibration. The uncertainties given in the parentheses correspond...
R Bacis - One of the best experts on this subject based on the ideXlab platform.
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Structure and rovibrational analysis of the [O_2 (^1Δ_g)_{v=0}]_2 \leftarrow [O_2 (^3 Σ^-_g)_{v=0}]_2 transition of the O_2 dimer
J.Chem.Phys., 2000Co-Authors: Ludovic Biennier, B Bussery-honvault, Alain Campargue, Daniele Romanini, Alexander Kachanov, R BacisAbstract:The Rotationally resolved absorption spectrum of the O/sub 2/ dimer\ninvolving the O/sub 2/(/sup 1/ Delta /sub g/)/sub v=0//sub 2/ from\nO/sub 2/(/sup 3/ Sigma /sub g//sup -/)/sub v=0//sub 2/ transition\nhas been recorded near 632.6 nm by continuous wave Cavity Ring Down\nSpectroscopy in a supersonic slit jet expansion of pure O/sub 2/.\nA quadratic dependence of the absorption in the jet versus the stagnation\npressure is observed. A Rotational temperature of 12 K is derived\nfrom the (O/sub 2/)/sub 2/ Rotational analysis. The high spectral\nresolution of the CW-CRDS measurements limited by the residual Doppler\nbroadening in the jet and the low Rotational temperature allow the\nfirst Rotational analysis in this open-shell complex. The same spectrum\nwas also recorded by Intracavity Laser Absorption Spectroscopy and\nthe comparison of the performances of the two methods is discussed.\nAmong more than 600 lines measured between 15 800 and 15 860 cm/sup\n-1/ from the CW-CRDS spectrum, 40 were assigned to the /sup R/P/sub\n0/, /sup R/Q/sub 0/, and /sup R/R/sub 0/ branches of two subbands\nassociated with B/sub 1//sup -/ from A/sub 1//sup +/ and A/sub 1//sup\n+/ from B/sub 1//sup -/ transitions between the ground and excited\nrovibrational levels, labeled following the G/sub 16/ permutation\ninversion representation. Forty five lines were assigned to /sup\nP/P/sub 2/, /sup P/Q/sub 2/, and /sup P/R/sub 2/ branches of two\nsubbands associated with B/sub 1//sup -/ from A/sub 1//sup +/ and\nA/sub 1//sup +/ from B/sub 1//sup -/ transitions. The subbands centered\nat 15 808.401(49) A/sub 1//sup +/ from B/sub 1//sup -/ and 15 813.134(37)\ncm/sup -1/ B/sub 1//sup -/ from A/sub 1//sup +/ for those arising\nfrom K=0, and at 15 812.656(20) A/sub 1//sup +/ from B/sub 1//sup\n-/ and 15 818.277(35) B/sub 1//sup -/ from A/sub 1//sup +/ when arising\nfrom K=2, are analyzed considering (O/sub 2/)/sub 2/ as a slightly\nasymmetric prolate top. The Rotational analysis of the two K=0 subbands\nleads to very close values of the effective Rotational Constant,\nB/sub p/=(B+C)/2, for both A/sub 1//sup +/ and B/sub 1//sup -/ levels:\n0.095 cm/sup -1/ for the O/sub 2/(/sup 3/ Sigma /sub g//sup -/)/sub\nv=0//sub 2/ lower states and 0.063 cm/sup -1/ for the O/sub 2/(/sup\n1/ Delta /sub g/)/sub v=0//sub 2/ excited states, in close agreement\nwith theoretical values. The H geometry is confirmed as the most\nstable for the ground electronic singlet state. A distance between\nthe two monomers of 6.1 a/sub 0/ and 7.5 a/sub 0/ is derived for\nthe ground and excited singlet states. Similar results are obtained\nfrom the two K=2 subbands. A vibrational assignment is given for\nthe two Rotationally analyzed subbands (K=0) and proposed for the\nmain features of the whole band. (62 References)
Wolfgang Jager - One of the best experts on this subject based on the ideXlab platform.
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fourier transform microwave spectroscopy of hsibr exploring the si br bond through quadrupole hyperfine coupling
Journal of Chemical Physics, 2005Co-Authors: Brandon S Tackett, Dennis J Clouthier, Jennifer N Landry, Wolfgang JagerAbstract:The 101‐000(9–10GHz) and 202‐101(18–19GHz) Rotational transitions of HSiBr79 and HSiBr81 have been measured in a pulsed discharge jet expansion to an experimental uncertainty of ∼1kHz using Fourier transform microwave spectroscopy. The data have yielded an effective Rotational Constant, the centrifugal distortion Constant Dj, the bromine nuclear quadrupole coupling Constants, and the bromine nuclear spin-molecular rotation interaction parameter for both isotopomers. The derived parameters have been compared to their values calculated ab initio, and the nuclear quadrupole coupling tensor has been used to investigate the Si–Br bond, giving a σ bond ionic character of 0.60, a π bond character of 0.22, and a total Si–Br ionic character of 0.38. These bond characteristics have been compared to trends in other halosilylenes, silanes, and the analogous carbenes.
Kensuke Harada - One of the best experts on this subject based on the ideXlab platform.
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high resolution fourier transform emission spectroscopy of the a 2πi x 2πi band of the ocs ion
Journal of Chemical Physics, 2017Co-Authors: Kensuke Harada, Keiichi Tanaka, Yoshihiro Nakashima, Takehiko TanakaAbstract:High resolution Fourier transform emission spectroscopy of the A∼2Πi–X∼2Πi band of the OCS+ ion was performed in the UV region to observe the ν1 (CO stretch) progression bands (υ1 = 0 → 2–5) for both the Ω=3/2 and 1/2 spin components. Accurate molecular Constants including the Rotational Constants, B0 = 0.194 765(13) and 0.187 106(13) cm−1, and the spin-orbit interaction Constants, A0 = −381.0(56) and −126.5(56) cm−1, were determined for the X∼2Π and A∼2Π states, respectively, by the simultaneous analysis of the observed progression bands. The CO bond length (rCO = 1.2810 A) for the A∼2Π state, derived from the Rotational Constant B0 and Franck-Condon factors, is longer by 0.1756 A than that (1.1054 A) for the X∼2Π state, while the CS bond length for the A∼2Π state is shorter by 0.0905 A than that for the X∼2Π state. Pure Rotational transition frequencies in the ground X∼2Π state are predicted, as well as transition frequencies of the ν1 fundamental band, with the present molecular Constants.
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CO2 laser Stark spectroscopy of the ν4 band of SiHF3: The C0 Rotational Constant and vibrationally induced dipole moment
Journal of Chemical Physics, 1992Co-Authors: Kensuke Harada, Syuji Akao, Kazumi Miyachi, Keiichi Tanaka, Takehiko TanakaAbstract:The ν4 (SiF3 degenerate stretch) fundamental band of SiHF3 has been investigated by the CO2 laser Stark spectroscopy. The vibrationally induced dipole moment was found to give remarkable perturbations of the type (Δl,ΔK)=(2,−1) in the ν4 vibrational state under intense electric field. Several perturbation‐induced rovibrational transitions obeying the Δ(K−l)=±3 selection rules were observed in the Stark spectrum. The C0 Rotational Constant, which is otherwise hard to obtain for a symmetric top molecule, was determined to be 4134.73(71) MHz. The vibrationally induced dipole moment μr in the ν4 state was derived as ±0.034 38(17) D, the sign being experimentally indeterminable. The band origin, the Coriolis Constant Cζ4, and the vibration–rotation Constant αC4 are 999.581 076(30) cm−1, 2445.59(71) MHz, and 9.243(22) MHz, respectively. The dipole moment is 1.359 20(22) D in the ground state, and increases by 0.026 73(10) D on excitation of the ν4 vibration. The uncertainties given in the parentheses correspond...
