Spectroscopic characterization of isomerization transition states

被引：54

作者：

Baraban, Joshua H. ^{[1
]}

Changala, P. Bryan ^{[1
]}

Mellau, Georg Ch. ^{[2
]}

Stanton, John F. ^{[3
]}

Merer, Anthony J. ^{[4
,5
]}

Field, Robert W. ^{[1
]}

机构：

[1] MIT, Dept Chem, Cambridge, MA 02139 USA

[2] Univ Giessen, Inst Phys Chem, D-35392 Giessen, Germany

[3] Univ Texas Austin, Dept Chem & Biochem, Austin, TX 78712 USA

[4] Univ British Columbia, Dept Chem, Vancouver, BC V6T 1Z1, Canada

[5] Acad Sinica, Inst Atom & Mol Sci, Taipei 10617, Taiwan

来源：

SCIENCE | 2015年 / 350卷 / 6266期

关键词：

(A)OVER-TILDE(1)A(U) STATE; VIBRATIONAL SPACINGS; DIATOMIC-MOLECULES; ACETYLENE; DISSOCIATION; ENERGY; ROTATION; MODEL; HCN;

D O I：

10.1126/science.aac9668

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate amethod for extracting transition state energies and properties froma characteristic pattern found in frequency-domain spectra of isomerizing systems. This pattern-a dip in the spacings of certain barrier-proximal vibrational levels-can be understood using the concept of effective frequency, omega(eff). The method is applied to the cis-trans conformational change in the S-1 state of C2H2 and the bond-breaking HCN-HNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous ab initio calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders.

引用

页码：1338 / 1342

页数：5

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