ESR of the C6 molecule

Infrared laser spectroscopy of jet-cooled carbon clusters

“…The fact that the measured spin-spin interaction constant Av compares well with the ESR results of Van Zee et al [15,16] from studies in rare gas matrices confirms their assignment of the ESR lines. The ESR values of A~ in rare gas matrices are found to be smaller than the gas phase value, showing a larger decrease in Ar than in Ne.…”

“…Jln Ar matrices [15,16]. In Ne matrices [15,16]. 1Ground state effective C--C bond length defined as {[(ri/2) 2 + (ri/2 + rm) 2 + (ri/2 + rm + ro)2]/8"75} 1/2 where ri, rm, and ro are the inner, middle, outer bond lengths.…”

“…Recent experiments [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] as well as high level ab initio calculations [19][20][21][22][23][24][25][26][27][28][29][30] have largely vindicated the description originally put forth by Pitzer and Clementi [31] in 1959. Clusters with odd numbers of carbons possess linear singlet ground states, whereas even numbered clusters have two low-lying isomers, a triplet linear form and a singlet cyclic form.…”

“…The only experimental results on C6 available to date are from ESR and infrared absorption experiments in rare gas matrices. Van Zee et al [15,16] detected 3~ molecules in rare gas matrices by ESR and assigned them to linear C 6, C 8 and Cl0 clusters with cumulenic bonding. Recently, the assignments of the matrix infrared absorption bands, originally proposed by Thompson et al [32], were reexamined on both experimental [33] and theoretical [28] grounds, and the 1952 cm -1 band was attributed to the linear triplet form of C6.…”

The isomers of small carbon clusters

“…Based on these calculations, carbon clusters of n atoms were either linear (for n< 10) or formed monocyclic rings (for n> 10). More recent theoretical studies contradict these results and predict the existence of low-lying cyclic isomers of small even-numbered clusters (n=4, 6, or 8) [3,4,5]. Experiments were not able to confirm these new theoretical results and only linear species were reported to have been detected [6][7][8][9][10][11][12][13][14].…”