1
|
Nadoveza N, Panadés-Barrueta RL, Shi L, Gatti F, Peláez D. Analytical high-dimensional operators in canonical polyadic finite basis representation (CP-FBR). J Chem Phys 2023; 158:114109. [PMID: 36948837 DOI: 10.1063/5.0139224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
In the present work, we introduce a simple means of obtaining an analytical (i.e., grid-free) canonical polyadic (CP) representation of a multidimensional function that is expressed in terms of a set of discrete data. For this, we make use of an initial CP guess, even not fully converged, and a set of auxiliary basis functions [finite basis representation (FBR)]. The resulting CP-FBR expression constitutes the CP counterpart of our previous Tucker sum-of-products-FBR approach. However, as is well-known, CP expressions are much more compact. This has obvious advantages in high-dimensional quantum dynamics. The power of CP-FBR lies in the fact that it requires a grid much coarser than the one needed for the dynamics. In a subsequent step, the basis functions can be interpolated to any desired density of grid points. This is useful, for instance, when different initial conditions (e.g., energy content) of a system are to be considered. We show the application of the method to bound systems of increased dimensionality: H2 (3D), HONO (6D), and CH4 (9D).
Collapse
Affiliation(s)
- Nataša Nadoveza
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | | | - Lei Shi
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | - Fabien Gatti
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | - Daniel Peláez
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| |
Collapse
|
2
|
Voute A, Gatti F, Møller KB, Henriksen NE. Femtochemistry of bimolecular reactions from weakly bound complexes: computational study of the H + H'OD → H'OH + D or HOD + H' exchange reactions. Phys Chem Chem Phys 2021; 23:27207-27226. [PMID: 34850799 DOI: 10.1039/d1cp04391a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A full-dimensional wavepacket propagation describing the bimolecular exchange reactions H + H'OD → H'OH + D or HOD + H' initiated by photolysis of HCl in the hydrogen-bound complex (HCl)⋯(HOD) is reported. The dynamics of this reaction is carried out with the MCTDH method on an ab initio potential energy surface (PES) of H3O and the initial state is derived from the ground state wavefunction of the complex obtained by relaxation on its own electronic ground state ab initio PES. The description of the system makes use of polyspherical coordinates parametrizing a set of Radau and Jacobi vectors. The calculated energy- and time-resolved reaction probabilities show, owing to the large collision energies at play stemming from the (almost full) photolysis of HCl, that the repulsion between oxygen in the H'OD molecule and the incoming hydrogen atom is the main feature of the collision and leads to non-reactive scattering. No abstraction reaction products are observed. However, both exchange processes are still observable, with a preference in O-H' bond dissociation over that of O-D. The selectivity is reversed upon vibrational pre-excitation of the O-D stretching mode in the H'OD molecule. It is shown that, after the collision, the hydrogen atom of HCl does most likely not encounter the almost stationary chlorine atom again but we also consider the limit case where the H atom is forced to collide multiple times against H'OD as a result of being pushed back by the Cl atom.
Collapse
Affiliation(s)
- Alexandre Voute
- Department of Chemistry, Technical University of Denmark, Kemitorvet 206, 2800 Kongens Lyngby, Denmark.
| | - Fabien Gatti
- ISMO, Institut des Sciences Moléculaires d'Orsay - UMR 8214 CNRS/Université Paris-Saclay, F-91405 Orsay, France
| | - Klaus B Møller
- Department of Chemistry, Technical University of Denmark, Kemitorvet 206, 2800 Kongens Lyngby, Denmark.
| | - Niels E Henriksen
- Department of Chemistry, Technical University of Denmark, Kemitorvet 206, 2800 Kongens Lyngby, Denmark.
| |
Collapse
|
3
|
Karmakar S, Keshavamurthy S. Intramolecular vibrational energy redistribution and the quantum ergodicity transition: a phase space perspective. Phys Chem Chem Phys 2020; 22:11139-11173. [DOI: 10.1039/d0cp01413c] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The onset of facile intramolecular vibrational energy flow can be related to features in the connected network of anharmonic resonances in the classical phase space.
Collapse
Affiliation(s)
- Sourav Karmakar
- Department of Chemistry
- Indian Institute of Technology
- Kanpur
- India
| | | |
Collapse
|
4
|
Sur S, Ndengué SA, Quintas-Sánchez E, Bop C, Lique F, Dawes R. Rotationally inelastic scattering of O3–Ar: state-to-state rates with the multiconfigurational time dependent Hartree method. Phys Chem Chem Phys 2020; 22:1869-1880. [DOI: 10.1039/c9cp06501f] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rates of state-changing collisions are compared for different isotopologues of ozone from quantum scattering calculations with the MCTDH method.
Collapse
Affiliation(s)
- Sangeeta Sur
- Department of Chemistry
- Missouri University of Science & Technology
- Rolla
- USA
| | - Steve A. Ndengué
- Department of Chemistry
- Missouri University of Science & Technology
- Rolla
- USA
- ICTP-East African Institute for Fundamental Research
| | | | - Cheikh Bop
- LOMC – UMR 6294
- CNRS-Université du Havre
- F-76063 Le Havre
- France
| | - François Lique
- LOMC – UMR 6294
- CNRS-Université du Havre
- F-76063 Le Havre
- France
| | - Richard Dawes
- Department of Chemistry
- Missouri University of Science & Technology
- Rolla
- USA
| |
Collapse
|
5
|
Yuen CH, Lapierre D, Gatti F, Kokoouline V, Tyuterev VG. The Role of Ozone Vibrational Resonances in the Isotope Exchange Reaction 16O 16O + 18O → 18O 16O + 16O: The Time-Dependent Picture. J Phys Chem A 2019; 123:7733-7743. [PMID: 31408343 DOI: 10.1021/acs.jpca.9b06139] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We consider the time-dependent dynamics of the isotope exchange reaction in collisions between an oxygen molecule and an oxygen atom: 16O16O + 18O → 16O18O + 16O. A theoretical approach using the multiconfiguration time-dependent Hartree method was employed to model the time evolution of the reaction. Two potential surfaces available in the literature were used in the calculations, and the results obtained with the two surfaces are compared with each other as well as with results of a previous theoretical time-independent approach. A good agreement for the reaction probabilities with the previous theoretical results is found. Comparing the results obtained using two potential energy surfaces allows us to understand the role of the reef/shoulder-like feature in the minimum energy path of the reaction in the isotope exchange process. Also, it was found that the distribution of final products of the reaction is highly anisotropic, which agrees with experimental observations and, at the same time, suggests that the family of approximated statistical approaches, assuming a randomized distribution over final exit channels, is not applicable to this case.
Collapse
Affiliation(s)
- Chi Hong Yuen
- Department of Physics , University of Central Florida , Orlando , Florida 32816 , United States
| | - David Lapierre
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, UFR Sciences , BP 1039, 51687 Reims Cedex 2 , France
| | - Fabien Gatti
- Institut de Sciences Moléculaires d'Orsay, UMR-CNRS 8214, Université Paris-Sud, Université Paris-Saclay , 91405 Orsay , France
| | - Viatcheslav Kokoouline
- Department of Physics , University of Central Florida , Orlando , Florida 32816 , United States
| | - Vladimir G Tyuterev
- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, UFR Sciences , BP 1039, 51687 Reims Cedex 2 , France.,QUAMER Laboratory , Tomsk State University , 634000 Tomsk , Russia
| |
Collapse
|
6
|
Pérez JB, Arce JC. Quantum dynamics of the intramolecular vibrational energy redistribution in OCS: From localization to quasi-thermalization. J Chem Phys 2018; 148:214302. [PMID: 29884040 DOI: 10.1063/1.5026318] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report a fully quantum-dynamical study of the intramolecular vibrational energy redistribution (IVR) in the electronic ground state of carbonyl sulfide, which is a prototype of an isolated many-body quantum system with strong internal couplings and non-Rice-Ramsperger-Kassel-Marcus (RRKM) behavior. We pay particular attention to the role of many-body localization and the approach to thermalization, which currently are topics of considerable interest, as they pertain to the very foundations of statistical mechanics and thermodynamics. We employ local-mode (valence) coordinates and consider initial excitations localized in one local mode, with energies ranging from low to near the dissociation threshold, where the classical dynamics have been shown to be chaotic. We propagate the nuclear wavepacket on the potential energy surface by means of the numerically exact multiconfiguration time-dependent Hartree method and employ mean local energies, time-dependent and time-averaged populations in quantum number space, energy distributions, entanglement entropies, local population distributions, microcanonical averages, and dissociation probabilities, as diagnostic tools. This allows us to identify a continuous localization → delocalization transition in the energy flow, associated with the onset of quantum chaos, as the excitation energy increases up to near the dissociation threshold. Moreover, we find that at this energy and ∼1 ps the molecule nearly thermalizes. Furthermore, we observe that IVR is so slow that the molecule begins to dissociate well before such quasi-thermalization is complete, in accordance with earlier classical-mechanical predictions of non-RRKM behavior.
Collapse
Affiliation(s)
- J B Pérez
- Departamento de Química, Universidad del Valle, AA 25360 Cali, Colombia
| | - J C Arce
- Departamento de Química, Universidad del Valle, AA 25360 Cali, Colombia
| |
Collapse
|
7
|
|
8
|
Ndengué SA, Dawes R, Gatti F, Meyer HD. Resonances of HCO Computed Using an Approach Based on the Multiconfiguration Time-Dependent Hartree Method. J Phys Chem A 2015; 119:12043-51. [DOI: 10.1021/acs.jpca.5b04642] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steve Alexandre Ndengué
- Department
of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
| | - Richard Dawes
- Department
of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
| | - Fabien Gatti
- CTMM,
Institut Charles Gerhardt, UMR 5253, Univeristé de Montpellier II, Place Eugène Bataillon, 34095 Montpellier, France
| | - Hans-Dieter Meyer
- Theoretische
Chemie, Physikalisch-Chemisches Institut, Im Neuenheimer Feld 229, Universität Heidelberg, 69120 Heidelberg, Germany
| |
Collapse
|
9
|
Sala M, Gatti F, Guérin S. Coherent destruction of tunneling in a six-dimensional model of NHD2: A computational study using the multi-configuration time-dependent Hartree method. J Chem Phys 2014; 141:164326. [DOI: 10.1063/1.4900518] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Matthieu Sala
- Laboratoire Interdisciplinaire Carnot de Bourgogne UMR 6303 CNRS, Université de Bourgogne, BP 47870, F-21078 Dijon, France
| | - Fabien Gatti
- CTMM, Institut Charles Gerhardt (UMR 5253), CC1501, Université Montpellier II, F-34095 Montpellier, Cedex 05, France
| | - Stéphane Guérin
- Laboratoire Interdisciplinaire Carnot de Bourgogne UMR 6303 CNRS, Université de Bourgogne, BP 47870, F-21078 Dijon, France
| |
Collapse
|
10
|
Saab M, Sala M, Lasorne B, Gatti F, Guérin S. Full-dimensional control of the radiationless decay in pyrazine using the dynamic Stark effect. J Chem Phys 2014; 141:134114. [DOI: 10.1063/1.4896938] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mohamad Saab
- CTMM, Institut Charles Gerhardt Montpellier (UMR5253), CC 15001, Université Montpellier 2, F-34095 Montpellier, Cedex 05, France
| | - Matthieu Sala
- Laboratoire Interdisciplinaire Carnot de Bourgogne (UMR 6303) CNRS, Université de Bourgogne, BP 47870, F-21078 Dijon, France
| | - Benjamin Lasorne
- CTMM, Institut Charles Gerhardt Montpellier (UMR5253), CC 15001, Université Montpellier 2, F-34095 Montpellier, Cedex 05, France
| | - Fabien Gatti
- CTMM, Institut Charles Gerhardt Montpellier (UMR5253), CC 15001, Université Montpellier 2, F-34095 Montpellier, Cedex 05, France
| | - Stéphane Guérin
- Laboratoire Interdisciplinaire Carnot de Bourgogne (UMR 6303) CNRS, Université de Bourgogne, BP 47870, F-21078 Dijon, France
| |
Collapse
|
11
|
Schröder M, Meyer HD. Calculation of the vibrational excited states of malonaldehyde and their tunneling splittings with the multi-configuration time-dependent Hartree method. J Chem Phys 2014; 141:034116. [DOI: 10.1063/1.4890116] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
12
|
Sala M, Saab M, Lasorne B, Gatti F, Guérin S. Laser control of the radiationless decay in pyrazine using the dynamic Stark effect. J Chem Phys 2014; 140:194309. [DOI: 10.1063/1.4875736] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
13
|
Joubert-Doriol L, Lasorne B, Gatti F, Schröder M, Vendrell O, Meyer HD. Suitable coordinates for quantum dynamics: Applications using the multiconfiguration time-dependent Hartree (MCTDH) algorithm. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2011.12.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
14
|
Otto F, Gatti F, Meyer HD. Rovibrational energy transfer in collisions of H2with D2: a full-dimensional wave packet propagation study. Mol Phys 2012. [DOI: 10.1080/00268976.2012.667165] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
15
|
Sala M, Gatti F, Lauvergnat D, Meyer HD. Effect of the overall rotation on the cis–trans isomerization of HONO induced by an external field. Phys Chem Chem Phys 2012; 14:3791-801. [DOI: 10.1039/c2cp23709a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
16
|
GIESE KAI, LAHAV DORON, KÜHN OLIVER. ON THE MULTIDIMENSIONALITY OF INTRAMOLECULAR HYDROGEN BOND DYNAMICS: HYDROGEN TRANSFER AND IVR IN 3,7-DICHLOROTROPOLONE. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633604001264] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this work, we investigate the intramolecular vibrational energy redistribution associated with the hydrogen transfer in a derivative of tropolone, namely 3,7-dichlorotropolone. Our quantum simulation is based on the Cartesian reaction surface Hamiltonian together with the multi-configurational time-dependent Hartree approach for the wave-packet propagation. We compare results for two model systems with 6 and 14 dimensions, respectively. The 6D model accounts for the most strongly coupled modes, whereas the 14D model includes further modes with significantly weaker couplings. The linear absorption spectrum of both models shows the development of an OH-stretching band. Furthermore the results show that despite the fact, that the additional modes in the 14D system couple significantly weaker, there are qualitative differences in the decay behavior of an OH-stretching excitation. Limitations of the present reaction surface approach are also discussed.
Collapse
Affiliation(s)
- KAI GIESE
- Institut für Chemie, Physikalische und Theoretische Chemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - DORON LAHAV
- Institut für Chemie, Physikalische und Theoretische Chemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - OLIVER KÜHN
- Institut für Chemie, Physikalische und Theoretische Chemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| |
Collapse
|
17
|
Schröder M, Gatti F, Meyer HD. Theoretical studies of the tunneling splitting of malonaldehyde using the multiconfiguration time-dependent Hartree approach. J Chem Phys 2011; 134:234307. [DOI: 10.1063/1.3600343] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
|
18
|
Marquardt R, Sanrey M, Gatti F, Le Quéré F. Full-dimensional quantum dynamics of vibrationally highly excited NHD2. J Chem Phys 2010; 133:174302. [DOI: 10.1063/1.3496374] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
19
|
Bhattacharya S, Panda AN, Meyer HD. Multiconfiguration time-dependent Hartree approach to study the OH+H2 reaction. J Chem Phys 2010; 132:214304. [DOI: 10.1063/1.3429609] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
20
|
Tatchen J, Pollak E. Semiclassical on-the-fly computation of the S0→S1 absorption spectrum of formaldehyde. J Chem Phys 2009; 130:041103. [DOI: 10.1063/1.3074100] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
21
|
Doriol LJ, Gatti F, Iung C, Meyer HD. Computation of vibrational energy levels and eigenstates of fluoroform using the multiconfiguration time-dependent Hartree method. J Chem Phys 2008; 129:224109. [DOI: 10.1063/1.3020716] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
22
|
Pasin G, Iung C, Gatti F, Richter F, Léonard C, Meyer HD. Theoretical investigation of intramolecular vibrational energy redistribution in HFCO and DFCO induced by an external field. J Chem Phys 2008; 129:144304. [DOI: 10.1063/1.2991411] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
23
|
Otto F, Gatti F, Meyer HD. Rotational excitations in para-H2+para-H2 collisions: Full- and reduced-dimensional quantum wave packet studies comparing different potential energy surfaces. J Chem Phys 2008; 128:064305. [DOI: 10.1063/1.2826379] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
|
24
|
Richter F, Gatti F, Léonard C, Le Quéré F, Meyer HD. Time-dependent wave packet study ontrans-cisisomerization of HONO driven by an external field. J Chem Phys 2007; 127:164315. [DOI: 10.1063/1.2784553] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
25
|
Panda AN, Otto F, Gatti F, Meyer HD. Rovibrational energy transfer in ortho-H2+para-H2 collisions. J Chem Phys 2007; 127:114310. [PMID: 17887840 DOI: 10.1063/1.2776266] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the results of a full-dimensional quantum mechanical study of the rovibrational energy transfer in the collision between ortho-H2 and para-H2 in the energy range of 0.1-1.0 eV. The multiconfiguration time-dependent Hartree algorithm has been used to propagate the wave packets on the global potential energy surface by Boothroyd et al. [J. Chem. Phys. 116, 666 (2002)] and on a modification of this surface where the short range anisotropy is reduced. State-to-state attributes such as probabilities or integral cross sections are obtained using the formalism of Tannor and Weeks [J. Chem. Phys. 98, 3884 (1993)] by Fourier transforming the correlation functions. The effect of initial rotation of the diatoms on the inelastic and de-excitation processes is investigated.
Collapse
Affiliation(s)
- Aditya N Panda
- Theoretische Chemie, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany.
| | | | | | | |
Collapse
|
26
|
Iung C, Pasin G. Variational Calculation of Specific, Highly Excited Vibrational States in DFCO: Comparison with Experimental Data. J Phys Chem A 2007; 111:10426-33. [PMID: 17880188 DOI: 10.1021/jp0734272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A stimulated emission pumping spectra of jet-cooled DFCO performed by Crane et al. (J. Mol. Spectrosc. 1997, 183, 273) has provided a great number of ro-vibrational lines up to 9000 cm(-1) of excitation energy. By combining a Jacobi-Wilson (JW) approach with a Davidson scheme, we calculate the lines provided by the experiment up to 9000 cm(-1) using an ab initio global potential energy surface (PES) developed by Kato et al. (J. Chem. Phys. 1997, 107, 6114). Comparisons between experimental and calculated data provide a critical test of the quality of the PES used. We show that the variational calculated energies can be efficiently corrected by taking into account the error observed for the A' fundamental transitions nu(i) (i = 1, ..., 5) and the first overtone 2nu(6). A detailed analysis of the eigenstates obtained by the calculation allows one to quantify the coupling between the different modes. Such an information is essential to understand and predict the energy flow through a DFCO molecule that is initially excited.
Collapse
Affiliation(s)
- Christophe Iung
- Equipe de Chimie Théorique, Méthodologies et Modélisation, Institut Gerhardt, UMR 5253 CNRS-UMII-ENSCM, CC 014, Université Montpellier II 34095 Montpellier Cedex 05, France.
| | | |
Collapse
|
27
|
Manzhos S, Carrington T. Using neural networks to represent potential surfaces as sums of products. J Chem Phys 2007; 125:194105. [PMID: 17129087 DOI: 10.1063/1.2387950] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
By using exponential activation functions with a neural network (NN) method we show that it is possible to fit potentials to a sum-of-products form. The sum-of-products form is desirable because it reduces the cost of doing the quadratures required for quantum dynamics calculations. It also greatly facilitates the use of the multiconfiguration time dependent Hartree method. Unlike potfit product representation algorithm, the new NN approach does not require using a grid of points. It also produces sum-of-products potentials with fewer terms. As the number of dimensions is increased, we expect the advantages of the exponential NN idea to become more significant.
Collapse
Affiliation(s)
- Sergei Manzhos
- Département de chimie, Université de Montréal, Case Postale 6128, succursale Centre-ville, Montréal, (Québec) H3C 3J7, Canada.
| | | |
Collapse
|
28
|
Pasin G, Iung C, Gatti F, Meyer HD. Theoretical investigation of highly excited vibrational states in DFCO: Calculation of the out-of-plane bending states and simulation of the intramolecular vibrational energy redistribution. J Chem Phys 2007; 126:024302. [PMID: 17228949 DOI: 10.1063/1.2402920] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A previously developed modified Davidson scheme [C. Iung and F. Ribeiro, J. Chem. Phys. 121, 174105 (2005)] is applied to compute and analyze highly excited (nu2,nu6) eigenstates in DFCO. The present paper is also devoted to the simulations of the intramolecular vibrational energy redistribution (IVR) initiated by an excitation of the out-of-plane bending vibration (nnu6, n=2,4,6, . . . ,18, and 20). The multiconfiguration time-dependent Hartree method is exploited to propagate the corresponding six-dimensional wave packets. A comprehensive comparison with experimental data as well as with previous simulations of IVR in HFCO [G. Pasin et al. J. Chem. Phys. 124, 194304 (2006)] is presented.
Collapse
Affiliation(s)
- Gauthier Pasin
- Equipe de Chimie Théorique Méthodologies et Modélisations, Institut Gerhardt, UMR 5253 CNRS-UM II-ENSCM, CC 014, Université Montpellier II, F-34095 Montpellier, Cedex 05, France.
| | | | | | | |
Collapse
|
29
|
Meyer HD, Quéré FL, Léonard C, Gatti F. Calculation and selective population of vibrational levels with the Multiconfiguration Time-Dependent Hartree (MCTDH) algorithm. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2006.06.002] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
30
|
Pasin G, Gatti F, Iung C, Meyer HD. Theoretical investigation of intramolecular vibrational energy redistribution in highly excited HFCO. J Chem Phys 2006; 124:194304. [PMID: 16729811 DOI: 10.1063/1.2192499] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The present paper is devoted to the simulations of the intramolecular vibrational energy redistribution (IVR) in HFCO initiated by an excitation of the out-of-plane bending vibration [nnu(6)=2,4,6,...,18,20]. Using a full six-dimensional ab initio potential energy, the multiconfiguration time-dependent Hartree (MCTDH) method was exploited to propagate the corresponding six-dimensional wave packets. This study emphasizes the stability of highly excited states of the out-of-plane bending mode which exist even above the dissociation threshold. More strikingly, the structure of the IVR during the first step of the dynamics is very stable for initial excitations ranging from 2nu(6) to 20nu(6). This latter result is consistent with the analysis of the eigenstates obtained, up to 10nu(6), with the aid of the Davidson algorithm in a foregoing paper [Iung and Ribeiro, J. Chem. Phys. 121, 174105 (2005)]. The present study can be considered as complementary to this previous investigation. This paper also shows how MCTDH can be used to predict the dynamical behavior of a strongly excited system and to determine the energies of the corresponding highly excited states.
Collapse
Affiliation(s)
- Gauthier Pasin
- LSDSMS (UMR 5636-CNRS), CC 014, Université Montpellier II, F-34095 Montpellier Cedex 05, France.
| | | | | | | |
Collapse
|
31
|
Fujisaki H, Zhang Y, Straub JE. Time-dependent perturbation theory for vibrational energy relaxation and dephasing in peptides and proteins. J Chem Phys 2006; 124:144910. [PMID: 16626248 DOI: 10.1063/1.2191038] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Without invoking the Markov approximation, we derive formulas for vibrational energy relaxation (VER) and dephasing for an anharmonic system oscillator using a time-dependent perturbation theory. The system-bath Hamiltonian contains more than the third order coupling terms since we take a normal mode picture as a zeroth order approximation. When we invoke the Markov approximation, our theory reduces to the Maradudin-Fein formula which is used to describe the VER properties of glass and proteins. When the system anharmonicity and the renormalization effect due to the environment vanishes, our formulas reduce to those derived by and Mikami and Okazaki [J. Chem. Phys. 121, 10052 (2004)] invoking the path-integral influence functional method with the second order cumulant expansion. We apply our formulas to VER of the amide I mode of a small amino-acid like molecule, N-methylacetamide, in heavy water.
Collapse
Affiliation(s)
- Hiroshi Fujisaki
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA.
| | | | | |
Collapse
|
32
|
|
33
|
Gatti F, Otto F, Sukiasyan S, Meyer HD. Rotational excitation cross sections of para-H2+para-H2 collisions. A full-dimensional wave-packet propagation study using an exact form of the kinetic energy. J Chem Phys 2005; 123:174311. [PMID: 16375532 DOI: 10.1063/1.2085167] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A full-dimensional quantum dynamical study of the rotational excitation in para-para H2 + H2 collisions using the potential-energy surface of Boothroyd et al. [J. Chem. Phys. 116, 666 (2002)] is reported. The multiconfiguration time-dependent Hartree algorithm is utilized to propagate wave packets and the cross sections for collision energies up to 1.2 eV are determined by a flux analysis through the interaction of the wave packet with a complex absorbing potential. Calculations for a collection of total angular momenta up to J = 70 are performed; the missing channels are obtained with a J-interpolation algorithm.
Collapse
Affiliation(s)
- Fabien Gatti
- LSDSMS Unite Mixte de Recherche 5636-Centre National de la Recherche Scientifique, CC 014, Université Montpellier II, F-34095 Montpellier, Cedex 05, France.
| | | | | | | |
Collapse
|
34
|
Pouilly B, Monnerville M, Gatti F, Meyer HD. Wave packet study of the UV photodissociation of the Ar2HBr complex. J Chem Phys 2005; 122:184313. [PMID: 15918710 DOI: 10.1063/1.1891725] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The photodissociation dynamics of the Ar2HBr van der Waals molecule is studied using the multiconfiguration time-dependent Hartree method. Standard Jacobian coordinates are used to describe the molecule. Two four-dimensional calculations are carried out where the rotation of the Ar2 molecule and, in addition, either the vibration of Ar2-Br or that of Ar2 are frozen. The time-evolution of the probability density in the different modes and the calculation of the dissociative flux show that the dissociating hydrogen atom preferentially moves out of the plane defined by Ar2 and Br. A comprehensive study of the cage effect in the process is presented.
Collapse
Affiliation(s)
- B Pouilly
- Unité Mixte de Recherche (UMR) 8523, Centre d'Etudes et de Recherches Lasers et Applications, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq Cédex, France.
| | | | | | | |
Collapse
|
35
|
Cattarius C, Meyer HD. Multidimensional density operator propagations in open systems: Model studies on vibrational relaxations and surface sticking processes. J Chem Phys 2004; 121:9283-96. [PMID: 15538849 DOI: 10.1063/1.1807392] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
An efficient method for the numerical treatment of multidimensional dynamics of open systems is presented: the multiconfiguration time-dependent Hartree (MCTDH) method extended to the propagation of density operators. With this method we investigate the relaxation process of a CO molecule adsorbed on a copper surface, i.e., CO/Cu(100), after the excitation with an infrared (IR) pulse. The interaction potential was taken from the literature. Lifetime estimations and thermalization studies were performed on the IR excited CO molecule. We were able to treat this system with all six degrees of freedom (DOF) and thus 12 dynamical variables, but most of our studies used a two or four DOF model. Finally, we demonstrate the applicability of MCTDH to the analysis of scattering processes in an open environment. We calculate sticking coefficients of a scattered particle to a model surface, the latter acting as heat bath. The surface corrugation and the initial particle energy have been varied, and six different relaxation strengths have been studied. These calculations were done under the inclusion of three DOFs: the two surface coordinates and the distance between the particle and the surface.
Collapse
Affiliation(s)
- Christoph Cattarius
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany.
| | | |
Collapse
|