An ab initio prediction of structures and vibrational frequencies of high-energy rotamers of glyoxal and acrolein

NIST-JANAF Thermochemical Tables. I. Ten Organic Molecules Related to Atmospheric Chemistry

“…It has been shown both spectroscopically [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] and theoretically [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] that glyoxal (OvCH-CHvO) undergoes rotational isomerization and exists in two planar, trans and cis, forms. The structure of the more stable trans conformer has been determined by a combination of electron diffraction and rotational data.…”

“…36 In general, these experimental geometries are in good agreement with theoretical results. 24,26,28,[33][34][35][38][39][40][41][42][43] The product of the principal moments of inertia for the planar structure of trans-glyoxal of C 2h symmetry was calculated here using the rotational constants determined from a high-resolution Fourier-transform study of trans-glyoxal. 15 Structural parameters of transglyoxal given above are those obtained from an electron diffraction investigation.…”

“…17,18 Sets of possible structural parameters of cisglyoxal were evaluated using the rotational constants for its isotopomers combined with assumptions of the values of some parameters. 7,8,10,28,44 The geometry of cis-glyoxal was also calculated by ab initio 22,24,[26][27][28][29][31][32][33]35,38,39,41,42 and molecular mechanics 43 methods. Structural parameters of cisglyoxal shown above were proposed by Tyulin et al 44 from analysis of microwave data.…”

“…[56][57][58] The experimental assignments have been confirmed by normal coordinate analyses 44,[59][60][61][62][63][64] and theoretical calculations. 26,28,29,31,34,35,40,43,[65][66][67][68][69][70] The adopted values for vibrational frequencies of trans-glyoxal were taken from the investigation of dispersed fluorescence spectra 53…”

“…The adopted values of 1 Ϫ 7 and 10 fundamental frequencies of cis-glyoxal are those observed from gas and Ar-matrix spectra. 13,18,55,58 For unobserved frequencies ( 8 , 9 , 11 , 12 ), the values were selected on the basis of ab initio calculations; 28,31,35,68 and their uncertainties are estimated to be 25-50 cm Ϫ1 .…”