Effects of probe energy and competing pathways on time-resolved photoelectron spectroscopy: the ring-opening of 1,3-cyclohexadiene

Abstract

The ring-opening dynamics of 1,3-cyclohexadiene (CHD) following UV excitation is studied using a model based on quantum molecular dynamics simulations with the ab initio multiconfigurational Ehrenfest (AI-MCE) method coupled to the Dyson orbital approach for photoionisation cross sections.Time-dependent photoelectron spectra are calculated for probe photon energies in the range 2-15 eV. The calculations demonstrate the value of universal high-energy probes, capable of tracking the dynamics in full, but also the utility of more selective lower-energy probes with a more restricted ionisation range. The predicted signal, especially with the universal probes, becomes highly convoluted due to the contributions from multiple reaction paths, rendering interpretation challenging unless complementary measurements and theoretical comparisons are available.

Studi Termodinamika Transpor Ionik Natrium Klorida Dalam Air dan Campuran Tertentu

“…Oleh karena itu,atom natrium lebih mudah kehilangan elektron pada kulit terluarnyadan menjadi bermuatan positif dari pada menjadi bermuatan negatif. Oleh karena itu, energi ionisas i (82)(83)(84)(85)(86) pertamanya cukup rendah yaitu pada 495,8 kj/mol. Sebaliknya, energi (87)(88)(89)(90)(91) ionisasi (92)(93)(94)(95)(96)(97)(98)(99)(100)(101) kedua sangat tinggi (4562 kj/mol), karna elektron pada kulit L lebih dekat ke ini atom.…”

Arresting doubly excited electronic state mediating lightning speed ring-opening reaction of 1,3-cyclohexadiene

“…Ultrafast photoionization mass spectrometry by Fuß and coworkers reported decades ago 5,7,8 inspired a number of subsequent studies on this benchmark system. 5,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27 Fuß et al employed strong field ionization of the transient species using 800 nm pulses, and suggested the wave packet propagation time on the 1 1 B surface, the time for transition from the 1 1 B to 2 1 A states, and the lifetime of the 2 1 A state to be 21, 35 and 80 fs, respectively. 7 Although the claims by Fuß et al were intriguing, definitive spectroscopic assignments of the ionized species and electronic states were lacking in their mass spectrometric study, leaving a large degree of ambiguity in their arguments.…”

Correspondence between electronic structure calculations and simulations: nonadiabatic dynamics in CS2

“…[13][14][15][16][17][18][19] Mechanistic interpretation of the experimental observations often involves comparison to simulations, making it possible to pull out features not immediately obvious from experiments alone. [20][21][22][23][24][25] There are also increasing efforts towards the calculation of observables directly from simulations, 20,[25][26][27][28][29] further strengthening the links between experiments and theory.…”

“…These methods are therefore increasingly becoming the default choice for the interpretation of experiments. 7,[20][21][22]25,[41][42][43] However, the ab initio electronic structure calculations, which ultimately constrain the fidelity of the simulations, 44 remain a severe computational bottleneck. Invariably, a compromise between the ideal level of electronic structure theory for the simulations and the level commensurate with available computational resources must be struck.…”