Browsing Artikler, rapporter og annet (kjemi) by Author "Alam, MD Mehboob"

Now showing items 1-6 of 6

    • Benchmarking the Performance of Exchange-Correlation Functionals for Predicting Two-Photon Absorption Strengths 

      Beerepoot, Maarten; Alam, MD Mehboob; Bednarska, Joanna; Bartkowiak, Wojciech; Ruud, Kenneth; Zaleśny, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-31)
      The present work investigates the performance of exchange–correlation functionals in the prediction of two-photon absorption (2PA) strengths. For this purpose, we considered six common functionals used for studying 2PA processes and tested these on six organoboron chelates. The set consisted of two semilocal (PBE and BLYP), two hybrid (B3LYP and PBE0), and two range-separated (LC-BLYP and CAM-B3LYP) ...

    • Channel interference in multiphoton absorption 

      Alam, MD Mehboob; Beerepoot, Maarten; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-30)
      We extend the theory of channel interference to higher-order multiphoton absorption processes. We derive an explicit expression for channel interference in a three-photon absorption process and propose a general scheme for deriving such expressions for multiphoton absorption processes of any order. Based on this general scheme, we derive and analyze the simplest few-state models for multiphoton ...

    • Choosing Bad versus Worse: Predictions of Two-Photon-Absorption Strengths Based on Popular Density Functional Approximations 

      Chołuj, Marta; Alam, MD Mehboob; Beerepoot, Maarten; Sitkiewicz, Sebastian P.; Matito, Eduard; Ruud, Kenneth; Zaleśny, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-26)
      We present a benchmark study of density functional approximation (DFA) performances in predicting the two-photon-absorption strengths in π-conjugated molecules containing electron-donating/-accepting moieties. A set of 48 organic molecules is chosen for this purpose, for which the two-photon-absorption (2PA) parameters are evaluated using different DFAs, including BLYP, PBE, B3LYP, PBE0, CAM-B3LYP, ...

    • Effect of donor–acceptor orientation on solvent-dependent three-photon activity in through-space charge-transfer systems – case study of [2,2]-paracyclophane derivatives 

      Alam, MD Mehboob; Chattopadhyaya, Mausumi; Chakrabarti, Swapan; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      We study the effect of donor–acceptor orientation on solvent-dependent three-photon transition probabilities (δ3PA) of representative through-space charge-transfer (TSCT) systems, namely, doubly positively charged [2,2]-paracyclophane derivatives. Our cubic response calculations reveal that the value of δ3PA may be as high as 106 a.u., which can further be increased by a specific orientation of the ...

    • A generalized few-state model for the first hyperpolarizability 

      Alam, MD Mehboob; Beerepoot, Maarten; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-22)
      The properties of molecules depend on their chemical structure, and thus, structure–property relations help design molecules with desired properties. Few-state models are often used to interpret experimental observations of non-linear optical properties. Not only the magnitude but also the relative orientation of the transition dipole moment vectors is needed for few-state models of the non-linear ...

    • Interplay of twist angle and solvents with two-photon optical channel interference in aryl-substituted BODIPY dyes 

      Alam, MD Mehboob; Misra, Ramprasad; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-11)
      Channel interference plays a crucial role in understanding the physics behind multiphoton absorption processes. In this work, we study the role of channel interference and solvent effects on the two-photon absorption in aryl-substituted boron dipyrromethene (BODIPY) dyes, a class of intramolecular charge-transfer (ICT) molecules. For this purpose, we consider fourteen dyes of this class with various ...