High resolution spectroscopy of carboxylic acid in the gas phase:: Observation of proton transfer in (DCOOH)2

被引:158
作者
Madeja, F [1 ]
Havenith, M [1 ]
机构
[1] Ruhr Univ Bochum, Inst Phys Chem 2, D-44780 Bochum, Germany
关键词
D O I
10.1063/1.1507581
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We report the first fully analyzed high resolution spectrum of a carboxylic acid dimer in the gas phase. High resolution spectra in the region of the C-O stretch 1241.7-1250.7 cm(-1) have been recorded for (DCOOH)(2). The data could be fit within experimental uncertainty to a rigid rotor Watson S reduced Hamiltonian. The vibrational frequency of the C-O stretch in (DCOOH)(2) is determined to be 1244.8461 (2) cm(-1). Our spectra are the first direct experimental evidence for proton transfer tunneling in formic acid dimer (FAD), with FAD serving as a prototype for double hydrogen bonded organic complexes. Previous theoretical studies predicted proton transfer times covering a range of several orders of magnitude. Our measurements on (DCOOH)(2) established a proton transfer time of 5.8 ns [tunneling splitting of 0.00286(25) cm(-1)]. The proton transfer was found to accelerate upon vibrational excitation of the skeleton motion (the vibrational C-O mode), corresponding to a tunneling splitting of 0.00999(21) cm(-1). For this state the proton transfer time decreased to 1.7 ns, which corresponds to a vibrationally enhanced proton transfer mechanism. The moments of inertia are in agreement with a C-2h structure which indicates a high tunneling barrier. The observed spin statistical weights follow a description of formic acid dimer in the molecular symmetry group G(8), which is isomorphic to the point group D-2h. Our results suggest an out-of-plane contribution to the proton transfer mechanism for the otherwise planar dimer. (C) 2002 American Institute of Physics.
引用
收藏
页码:7162 / 7168
页数:7
相关论文
共 41 条
[1]   HOW RELIABLE ARE CALCULATIONS ON PROTON TUNNELING [J].
AGRESTI, A ;
BACCI, M ;
RANFAGNI, A .
CHEMICAL PHYSICS LETTERS, 1981, 79 (01) :100-104
[2]   A REINVESTIGATION OF STRUCTURE OF MONOMER AND DIMER FORMIC ACID BY GAS ELECTRON DIFFRACTION TECHNIQUE [J].
ALMENNINGEN, A ;
BASTIANSEN, O ;
MOTZFELDT, T .
ACTA CHEMICA SCANDINAVICA, 1969, 23 (08) :2848-+
[3]   A link between protein structure and enzyme catalyzed hydrogen tunneling [J].
Bahnson, BJ ;
Colby, TD ;
Chin, JK ;
Goldstein, BM ;
Klinman, JP .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1997, 94 (24) :12797-12802
[4]   THE RAMAN-ACTIVE O-H AND O-D STRETCHING VIBRATIONS AND RAMAN-SPECTRA OF GASEOUS FORMIC ACID-D1 AND ACID-OD [J].
BERTIE, JE ;
MICHAELIAN, KH ;
EYSEL, HH ;
HAGER, D .
JOURNAL OF CHEMICAL PHYSICS, 1986, 85 (09) :4779-4789
[5]   STRUCTURE AND TUNNELING DYNAMICS OF MALONALDEHYDE - A THEORETICAL-STUDY [J].
BICERANO, J ;
SCHAEFER, HF ;
MILLER, WH .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1983, 105 (09) :2550-2553
[6]  
Bunker P. R., 1998, MOL SYMMETRY SPECTRO
[7]   AN ANALYSIS OF THE INFRARED AND RAMAN-SPECTRA OF THE FORMIC-ACID DIMER (HCOOH)2 [J].
CHANG, YT ;
YAMAGUCHI, Y ;
MILLER, WH ;
SCHAEFER, HF .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1987, 109 (24) :7245-7253
[8]  
*EPAPS, EJCPSA6117016239 EPA
[9]   PROTON-TRANSFER IN THE ADENINE-THYMINE BASE-PAIR [J].
FLORIAN, J ;
HROUDA, V ;
HOBZA, P .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1994, 116 (04) :1457-1460
[10]  
Gantenberg M, 2000, CHEM-EUR J, V6, P1865, DOI 10.1002/(SICI)1521-3765(20000515)6:10<1865::AID-CHEM1865>3.0.CO