| 1. |
- Macak, Peter, et al.
(författare)
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Two-photon excitations in molecules
- 2003
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Ingår i: Non-linear optical responses of molecules,solids and liquids: Methods and applications. - : Plenum Publishing.
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Bokkapitel (refereegranskat)abstract
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| 2. |
- Baev, Alexander, et al.
(författare)
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Upconverted lasing based on many-photon absorption : an all dynamic description
- 2004
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Ingår i: Journal of the Optical Society of America. B, Optical physics. - 0740-3224 .- 1520-8540. ; 21:2, s. 384-396
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Tidskriftsartikel (refereegranskat)abstract
- A theory is developed for the propagation through a nonlinear medium of strong pump and amplifiedspontaneous-emission pulses. The theory is based on a solution of the density matrix equations that aims at providing an adequate treatment of the nonlinear polarization of the material without addressing the Taylor expansion over the powers of intensity. The theory has been applied for modeling of three-photon absorption induced upconverted stimulated emission of organic molecules in solvents. Numerical results are presented for the organic chromophore 4-[N-(2-hydroxyethyl)-N-(methyl)amino phenyl]-4'-(6-hydroxyhexyl sulfonyl) stilbene dissolved in dimethyl sulfoxide. The results are in good agreement with available experimental results.
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| 3. |
- Cronstrand, Peter, et al.
(författare)
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Ab initio calculations of three-photon absorption
- 2003
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Ingår i: Chemical Physics Letters. - : Elsevier. - 0009-2614 .- 1873-4448. ; 375:02-jan, s. 233-239
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Tidskriftsartikel (refereegranskat)abstract
- We present large scale ab initio calculations of three-photon absorption of a series of dithienothiophene based charge transfer molecules using response theory within the random phase approximation. The structure-to-property relations obtained for the three-photon absorption cross-sections are discussed and compared with those for one- and two-photon absorption.
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| 4. |
- Cronstrand, Peter, 1965, et al.
(författare)
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Electrochemical leaching of cementitious materials: an experimental and theoretical study
- 2011
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Ingår i: Procedings of the 1st International Symposium on Cement-Based Materials for Nuclear Wastes, NUMCEM 2011. ; Session 3:Paper O344
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Konferensbidrag (refereegranskat)abstract
- The acceleration of aging processes using forced ionic migration has been studied from a combined theoretical and experimental point of view. The preliminary results indicate that only a fraction of the reactive-transport through the sample is associated with dissolution of portlandite and the subsequent release of calcium. Further experimental work is needed in order to characterize the sample in terms of mineral composition and microstructure and to verify the modeling approach.
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| 5. |
- Cronstrand, Peter, et al.
(författare)
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Few-states models for three-photon absorption
- 2004
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Ingår i: Journal of Chemical Physics. - : American Institute of Physics (AIP). - 0021-9606 .- 1089-7690. ; 121:5, s. 2020-2029
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Tidskriftsartikel (refereegranskat)abstract
- Few-states models are derived for the calculation of three-photon absorption matrix elements. Together with earlier derived few-states models for two-photon absorption, the models are evaluated against results from response theory calculations that provide the full sum-over-states values. It is demonstrated that not even for systems with charge-transfer character, where few-states models for two-photon absorption are in excellent agreement with response theory, do the models provide a quantitatively correct description for three-photon absorption. The convergence behavior, merits, and shortcomings of the models are elucidated in some detail. The role of various characteristics of the electronic structure, such as symmetry, charge transfer, and conjugation-important for the formation of a large three-photon cross section-is analyzed. As for two-photon absorption cross sections, it is essential to consider generalized few-states models also for three-photon absorption, that is, to account for dipolar directions and laser beam polarization. Despite their poor quantitative performance, it is argued that few-states models at times can be useful for interpretation purposes when applied to three-photon absorption.
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| 6. |
- Cronstrand, Peter, et al.
(författare)
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Multi-photon absorption of molecules : A TRIBUTE TO JAN LINDERBERG AND POUL JORGENSEN
- 2005
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Ingår i: ADVANCES IN QUANTUM CHEMISTRY, VOL 50: A TRIBUTE TO JAN LINDERBERG AND POUL JORGENSEN. - SAN DIEGO, CA : ELSEVIER ACADEMIC PRESS INC. - 0120348500 ; , s. 1-21
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Konferensbidrag (refereegranskat)abstract
- Recent applications of response theory formulations of Olsen and Jorgensen on multi-photon absorption of molecules have been briefly reviewed. The connection between the calculated microscopic and experimentally measured macroscopic properties is derived. The performance of various computational approaches ranging from Hartree-Fock and Coupled Cluster to Density Functional theory for these spectral properties is analyzed. Using analytic response theory results as reference, the validity of the commonly applied few-states models for two- and three-photon absorption of molecules have been examined. A design strategy for three-dimensional charge-transfer multi-photon absorption systems is presented.
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| 7. |
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| 8. |
- Cronstrand, Peter, 1969-
(författare)
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Quantum chemical calculations of non-linear optical absorption
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis represents a quantum chemical treatise ofvarious types of interactions between radiation and molecularsystems, with special emphasis on the nonlinear opticalprocesses of Multi-Photon Absorption and Excited StateAbsorption. Excitation energies, transition dipole moments,two-photon and three-photon tensor elements have beencalculated from different approaches; density functional theoryandab-initiotheory, employing different orders ofcorrelation treatment with the purpose to provide accuratevalues as well as evaluate the quality of the lower ordermethods. A combined study of the Multi-Photon Absorption andExcited State Absorption processes is motivated partly becausethey both contribute to the total optical response of a systemsubjected to intense radiation, but also because of theirconnection through so-called sum-over-states expressions. Thelatter feature is exploited in a generalized few-states model,which incorporates the polarization of the light and thedirections of the transition dipole moments constructing anexcitation channel, which thereby enables a more comprehensivecomparison of the attained transition dipole moments withexperimental data. Moreover, by decomposing a complex nonlinearresponse process such as Two-Photon Absorption into moreintuitive quantities, generalized few-states models may alsoenable a more elaborate interpretation of computed orexperimental results from which guidelines can be extracted inorder to control or optimize the property of interest. Ageneral conclusion originating from these models is that thetransition dipole moments in an excitation channel should bealigned in order to maximize the Two-Photon Absorptionprobability. The computational framework employed is responsetheory which through the response functions (linear, quadratic,cubic) offers alternative routes for evaluating the propertiesin focus; either directly and untruncated through the singleresidue of the quadratic or cubic response func- tions orthrough various schemes of truncated sum-over-statesexpressions where the key ingredients, transition dipolemoments, can be identified from the single residue of thelinear response function and double residue of the quadraticresponse function. The range of systems treated in the thesisstretches from diatomics, such as carbon monoxide and lithiumhydride, via small to large fundamental organic molecules, suchas formaldehyde, tetrazine and the trans-polyenes, to largechro- mophores, such astrans-stilbene, cumulenes, dithienothiophene,paracyclophane and organo-metallic systems, such as theplatinum(II)ethynyl compounds.
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| 9. |
- Cronstrand, Peter, et al.
(författare)
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Theoretical calculations of excited state absorption
- 2000
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 2:23, s. 5357-5363
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Tidskriftsartikel (refereegranskat)abstract
- Excitation energies and transition dipole moments between excited electronic states have been calculated using various theoretical methods to investigate the ability to describe excited state absorption. Quadratic response theory is used in combination with self-consistent field, multi-configurational self-consistent field, and coupled-cluster electronic structure methods. The results of these different methods are compared. The set of molecules considered includes lithium hydride, carbon monoxide, formaldehyde, formamide, and symtetrazine. For some of the molecules results are also compared with the method of applying linear response theory to an excited state wavefunction separately optimized by means of the multi-configurational self-consistent field method.
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