Molecular-beam spectrum of the 970 cm−1 Fermi triad of CF3CH3

Journal of Chemical Physics - Tập 99 Số 4 - Trang 2396-2404 - 1993
G. T. Fraser1, A. S. Pine1, José Luis Doménech1, Brooks H. Pate1
1Molecular Physics Division, National Institute of Standards and Technology, Gaithersburg, Maryland, 20899

Tóm tắt

A tunable microwave-sideband CO2 laser is used with an electric-resonance optothermal spectrometer to investigate the infrared spectrum of CF3CH3 near 970 cm−1. A Fermi-coupled triad of states is observed, resulting from the interactions of 2ν6+ν11 and ν5+ν12 with the fundamental vibration, ν10, which is assumed to carry the oscillator strength in this region. The high resolution (∼3 MHz) of the spectrometer allows the observation of tunneling splittings associated with the ν6 torsional vibration. These splittings are used to identify the torsional character of the states observed. At the normal-mode level the ν10 and ν5+ν12 states are found to be nearly degenerate and interacting by an anharmonic matrix element of ∼3 cm−1. The lower-energy component of this diad exhibits torsional splittings of up to 400 MHz due to an anharmonic coupling of 0.70 cm−1 with the lower energy 2ν6+ν11 state which has an intrinsic tunneling splitting of ∼800 MHz. A fourth state, 3ν6+ν12, which has a still larger zeroth-order tunneling splitting, may also be affecting the torsional splittings of the observed states. The present investigation illustrates the utility of using resolved torsional splittings to unravel complex vibrational couplings in molecules.  

Từ khóa


Tài liệu tham khảo

1985, J. Phys. Chem., 89, 3857, 10.1021/j100264a017

1986, J. Chem. Phys., 84, 4710, 10.1063/1.449999

1987, J. Chem. Phys., 86, 51, 10.1063/1.452591

1985, Annu. Rev. Phys. Chem., 36, 491, 10.1146/annurev.pc.36.100185.002423

1960, J. Chem. Phys., 33, 1008, 10.1063/1.1731324

1978, Spectrochim. Acta., 34A, 9

1984, Chem. Phys., 85, 1, 10.1016/S0301-0104(84)85167-8

1991, J. Am. Chem. Soc., 113, 4342, 10.1021/ja00011a054

1991, J. Chem. Phys., 95, 7041, 10.1063/1.461432

1992, J. Chem. Phys., 97, 2971, 10.1063/1.463038

1982, J. Res. Natl. Bur. Stand., 87, 237, 10.6028/jres.087.017

1989, J. Mol. Spectrosc., 137, 166, 10.1016/0022-2852(89)90278-6

1948, J. Chem. Phys., 16, 1002, 10.1063/1.1746666

1949, Phys. Rev., 75, 1319

1950, Phys. Rev., 78, 145, 10.1103/PhysRev.78.145

1957, J. Electrochem., 61, 935

1957, J. Am. Chem. Soc., 79, 2391, 10.1021/ja01567a013

1977, J. Mol. Spectrosc., 68, 166, 10.1016/0022-2852(77)90432-5

1978, Phys. Rev. Lett., 41, 1109, 10.1103/PhysRevLett.41.1109

1991, Chem. Phys., 152, 241, 10.1016/0301-0104(91)85003-Y

1950, J. Chem. Phys., 11, 1471

1950, J. Chem. Phys., 18, 1297

1952, J. Chem. Phys., 20, 473, 10.1063/1.1700444

1990, Nature (London), 344, 508, 10.1038/344508a0

1989, J. Chem. Phys., 90, 6077, 10.1063/1.456373

1989, J. Chem. Phys., 91, 637, 10.1063/1.457169

1991, J. Chem. Phys., 94, 7061, 10.1063/1.460239

1977, Appl. Phys. Lett., 30, 338, 10.1063/1.89390

1984, IEEE J. Quantum Electron., QE-20, 700

1986, IEEE J. Quantum Electron., QE-22, 234

1965, Mol. Phys., 9, 257, 10.1080/00268976500100331

See AIP document No. PAPS JCPSA-99-2396-10 for 10 pages of assigned transitions for CF3CH3.Order by PAPS number and journal reference from American Institute of Physics Auxiliary Publication Service, 500 Sunnyside Boulevard, Woodbury, New York 11797-2999. The price is $1.50 for each microfiche (60 pages) or $5.00 for photocopies of up to 30 pages, and $0.15 for each additional page over 30 pages. Airmail additional. Make checks payable to the American Institute of Physics.

Thông tin
Thông tin xuất bản

Journal of Chemical Physics

Tập 99 Số 4

2396-2404

Thông tin tác giả