Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Photoswitchable Molecular Units with Tunable Nonlinear Optical Activity: A Theoretical Investigation
Δημιουργός/Συγγραφέας:	Avramopoulos, Aggelos Reis, Heribert [EL] Τζέλη, Δήμητρα[EN] Tzeli, Demeter Zaleśny, Robert [EL] Παπαδόπουλος, Μάνθος Γ.[EN] Papadopoulos, Manthos G.
Εκδότης:	Molecules
Ημερομηνία:	2023-07-26
Γλώσσα:	Αγγλικά
ISSN:	1420-3049
DOI:	10.3390/molecules28155646
Άλλο:	37570617
Περίληψη:	The first-, second-, and third-order molecular nonlinear optical properties, including two-photon absorption of a series of derivatives, involving two dithienylethene (DTE) groups connected by several molecular linkers (bis(ethylene-1,2-dithiolato)Ni- (NiBDT), naphthalene, quasilinear oligothiophene chains), are investigated by employing density functional theory (DFT). These properties can be efficiently controlled by DTE switches, in connection with light of appropriate frequency. NiBDT, as a linker, is associated with a greater contrast, in comparison to naphthalene, between the first and second hyperpolarizabilities of the "open-open" and the "closed-closed" isomers. This is explained by invoking the low-lying excited states of NiBDT. It is shown that the second hyperpolarizability can be used as an index, which follows the structural changes induced by photochromism. Assuming a Förster type transfer mechanism, the intramolecular excited-state energy transfer (EET) mechanism is studied. Two important parameters related to this are computed: the electronic coupling (VDA) between the donor and acceptor fragments as well as the overlap between the absorption and emission spectra of the donor and acceptor groups. NiBDT as a linker is associated with a low electronic coupling, VDA, value. We found that VDA is affected by molecular geometry. Our results predict that the linker strongly influences the communication between the open-closed DTE groups. The sensitivity of the molecular nonlinear optical properties could assist with identification of molecular isomers.
Τίτλος πηγής δημοσίευσης:	Molecules (Basel, Switzerland)
Τόμος/Κεφάλαιο:	28
Τεύχος:	15
Θεματική Κατηγορία:	[EL] Χημεία[EN] Chemistry [EL] Οπτική. Φώς[EN] Optics. Light
Λέξεις-Κλειδιά:	(hyper)polarizability bis(ethylene-1,2-dithiolato) density functional theory dithienylethene excited-state energy transfer molecular switches photochromism two-photon absorption
Ηλεκτρονική διεύθυνση στον εκδότη (link):	https://www.mdpi.com/1420-3049/28/15/5646
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο