Wavelength-dependent Photodissociation Dynamics of Benzaldehyde

• Published in: Chinese journal of chemical physics Vol. 22; no. 6; pp. 587 - 591
• Main Authors: Liu, Ben-kang, Wang, Bing-xing, Wang, Yan-qiu, Wang, Li
• Format: Journal Article
• Language: English
• Published: IOP Publishing 27.12.2009
• Subjects: 光解动力学; 指数衰减; 振动能级; 波长; 碎片离子; 苯甲醛; 超快动力学; 飞行质谱; Femtosecond pump-probe; Benzaldehyde; Ultrafast process
• ISSN: 1674-0068; 2327-2244
• DOI: 10.1088/1674-0068/22/06/587-591

The ultrafast dynamics of benzaldehyde upon 260, 271, 284, and 287 nm excitations have been studied by femtosecond pinup-probe time-of-flight mass spectrometry. A bi-exponential decay component model was applied to fit the transient profiles of benzaldehyde ions and fragment ions. At the S2 origin, the first decay of the component was attributed to the internal conversion to the high vibrational levels of S1 state. Lifetimes of the first component decreased with increasing vibrational energy, due to the influence of high density of the vibrational levels. The second decay was assigned to the vibrational relaxation of the S1 whose lifetime was about 600 fs. Upon 287 nm excitation, the first decay became ultra-short （-56 fs） which was taken for the intersystem cross from S1 to T2, while the second decay component was attributed to the vibrational relaxation. The pump-probe transient of fragment was also studied with the different probe intensity at 284 nm pump.