Photochemical Chiral Symmetry Breaking in Alanine

Wohlgemuth, Matthias; Mitrić, Roland

doi:10.1021/acs.jpca.6b07611

Cited by 10 publications

(11 citation statements)

References 52 publications

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“…In agreement with the experiment on absorption of circularly polarized UV light, the molecular dynamics simulations based on the gradients obtained from the semi-empirical multireference OM2/MRCI method 897 have shown that photolysis leads to enantiomeric enrichment of either right-or left-handed enantiomer depending on the helicity of the laser field.…”

Section: Isolated Amino Acids and Small Peptide Modelssupporting

confidence: 78%

Multireference Approaches for Excited States of Molecules

et al. 2018

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Understanding the properties of electronically excited states is a challenging task that becomes increasingly important for numerous applications in chemistry, molecular physics, molecular biology, and materials science. A substantial impact is exerted by the fascinating progress in time-resolved spectroscopy, which leads to a strongly growing demand for theoretical methods to describe the characteristic features of excited states accurately. Whereas for electronic ground state problems of stable molecules the quantum chemical methodology is now so well developed that informed nonexperts can use it efficiently, the situation is entirely different concerning the investigation of excited states. This review is devoted to a specific class of approaches, usually denoted as multireference (MR) methods, the generality of which is needed for solving many spectroscopic or photodynamical problems. However, the understanding and proper application of these MR methods is often found to be difficult due to their complexity and their computational cost. The purpose of this review is to provide an overview of the most important facts about the different theoretical approaches available and to present by means of a collection of characteristic examples useful information, which can guide the reader in performing their own applications.

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Section: Isolated Amino Acids and Small Peptide Modelssupporting

confidence: 78%

Multireference Approaches for Excited States of Molecules

et al. 2018

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“…It is known that α-alanine has UV absorption bands located at ∼270 nm (4.59 eV, hereafter we refer to this state as S 1 ), 220 nm (5.64 eV, S 2 ), 190 nm (6.53 eV, S 3 ), and more at shorter wavelengths, with the S 2 band having the strongest absorbance of the three. , Numerous experimental and theoretical studies on the photodynamics of alanine have been reported, particularly focusing on enantioselective dissociations that lead to enantiomeric enrichment. − However, the main photoproducts of alanine dissociation have not been directly identified. In this work, we have investigated the photodissociation dynamics of α-alanine and its deuterated species in the S 1 and S 2 excited states in a p H 2 matrix.…”

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confidence: 99%

Hydrocarboxyl Radical as a Product of α-Alanine Ultraviolet Photolysis

Moore

Toh

Wong

et al. 2021

J. Phys. Chem. Lett.

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UV photodissociation of α-alanine was studied by parahydrogen matrix isolation infrared spectroscopy. The temporal behavior of Fourier transform infrared spectra revealed that UV irradiation at 213 nm yielded the HOCO radical as a direct photoproduct from the S 2 excited state. The concentration of HOCO quickly approached a steady state due to secondary photodissociation of HOCO to produce CO 2 + H or CO + OH. On the other hand, no photoproducts were detected by S 1 excitation at 266 nm. Irradiation of fully deuterated α-alanine at 213 nm yielded ∼2 times more cis-DOCO radicals than the lower energy isomer trans-DOCO, indicating that the conformation of the hydroxyl group is fairly well-preserved upon photodissociation of α-alanine. The present study suggests that HOCO may be a good tracer species in the search for amino acids in interstellar space.

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“…33 and 64 and later adapted to ADC(2). 65 The classical nuclear dynamics was simulated by integration of Newton's equations of motion using the velocity Verlet algorithm 66 with an integration time step of 0.2 fs. Considering the ground and the three energetically lowest excited states, the electronic population dynamics was determined along the classical trajectories by solving the time-dependent Schrödinger equation including the non-adiabatic couplings between all electronic states.…”

Section: Methodsmentioning

confidence: 99%