Is there a minimum polarizability principle in chemical reactions?

被引:110
|
作者
Hohm, U [1 ]
机构
[1] Tech Univ Braunschweig, Inst Phys & Theoret Chem, D-38106 Braunschweig, Germany
来源
JOURNAL OF PHYSICAL CHEMISTRY A | 2000年 / 104卷 / 36期
关键词
D O I
10.1021/jp0014061
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
For complete fragmentations of the type A(m)B(n...) --> mA + nB + ... the change of the dipole polarizabilty Delta alpha = Sigma(i)nu(i)alpha(i) and its cube-root Delta alpha(CR) = Sigma(i)nu(i)alpha(i)(1/3) in as well as the atomization energy D-at are calculated from literature data (nu(i) is the stoichiometric coefficient). We have taken into account a large number of molecules containing the atoms H, C, N, O, S, P, F, Cl, Br, and I as well as the metals Fe and Os. The ranges of D-at and Sigma(i)nu(i)alpha(i) covered by the fragmentations are between 150 and 15 000 kJ mol(-1) and -6 and 170 x 10(-41) C-2 m(2) J(-1), respectively. In most cases Delta alpha > 0 is observed, whereas we always find Delta alpha(CR) > 0. Additionally, we observe a linear relationship D-at = A(mu) + B mu Sigma(i)nu(i)alpha(i)(u) between the atomization energy D-at and the sum of the dipole-polarizabilities of all chemical species taking part in the fragmentation. The linear relation is obtained for mu = 1 and 1/3. Our observation implies that the most stable isomer has the lowest polarizability and that in chemical reactions the most stable species (reactants or products) have the lowest sum of alpha(1/3).
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页码:8418 / 8423
页数:6
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