Electronic states of azabenzenes: A critical review

Dynamics of radiationless transitions in large molecular systems: A Franck–Condon-based method accounting for displacements and rotations of all the normal coordinates

“…Indeed, that problem has attracted considerable interest over the past years and therefore experimental and theoretical data are abundant in the literature. [37][38][39][40][41][42][43][44][45][46][47] The absorption spectrum of pyrazine exhibits a well structured band for the S 0 → S 1 (π, π * ) transition and a broad, less structured band for the S 0 → S 2 (n, π * ) one. 37,38 The most significant feature of the S 1 absorption band is the presence of an anharmonic progression of the b 1g mode (ν 10a ); since the molecular symmetry (D 2h ) is retained upon transition to S 1 , 43,46,48 odd transitions of that progression are not allowed in the Franck-Condon approximation (strong frequency variation could be responsible for even transitions), so that other mechanisms must be invoked.…”

A Concerted Triple Dissociation : The Photochemistry of S-Tetrazine

“…[3][4][5][6][7][8][9] In contrast to the spectroscopy, a consensus has not been reached on the photochemistry of ST, as far as the dissociation mechanism is concerned. 3 Since an extensive review of the controversy over the suggested dissociation mechanism has been 3 given in a recent publication by Scheiner and Schaefer (SS), we will only emphasize a few important points.…”

Study of Coordination Characteristics of some Metal Complexes of 2-Thiouracil by Infrared Spectroscopy

“…The assignments given in the TABLE I were established after careful consideration of the assignments available for related molecules like Pyrimidine-2-thione [15], [22], 4,6-dimethyl pyrimidine-2-thione [15], 1,4,5,6-tetrahydropyrimidine-2-thione [15], 2-pyrimidone [16], 2-chloropyrimidine [17], pyrimidine [18], cytosine [19], thiocytosine and other related compounds. The general procedure followed for empirical assignments of thioureide frequencies are (i) Ndeuteration studies (ii) S-methylation studies (iii) selenation technique (iv) study of polarization characteristics of infrared bands in the oriented crystalline samples [20].…”

“…The general procedure followed for empirical assignments of thioureide frequencies are (i) Ndeuteration studies (ii) S-methylation studies (iii) selenation technique (iv) study of polarization characteristics of infrared bands in the oriented crystalline samples [20].…”