1
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Koushki AM. High-order harmonic generation from aligned HCN molecules under orthogonally and linearly polarized two-color laser fields. J Mol Model 2023; 29:137. [PMID: 37052706 DOI: 10.1007/s00894-023-05544-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
Molecular high-order harmonic generation and molecular orbital ionization probabilities are calculated under orthogonally and linearly polarized two-color laser fields. When a second-harmonic field is applied, the high-order harmonics generated under the linearly polarized two-color laser fields in the antiparallel case are stronger than those generated in the orthogonal polarization case and even stronger than those of the parallel polarization case. The results show that ionization probabilities of various orbitals and harmonic orders are dependent on spatial symmetry of molecular orbitals. It is found that the ionization of low-lying Kohn-Sham molecular orbitals contributes significantly to the ionization and molecular high-order harmonic generation processes. The ionization probability maximum occurs when molecular orbital densities are maximum in the direction of laser field polarization. Furthermore, we show that the degeneracy of π orbitals is broken when the laser-molecule alignment angle deviates from the field axis. Accordingly, we indicated one component of the π orbital is effectively contributed to the ionization and high-order harmonic generation processes. Finally, to confirm the recollision model in the high-order harmonic generation, the quantum time-frequency analysis is used to extract electron paths information on subcycle time scales.
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Affiliation(s)
- A M Koushki
- Photonics and Quantum Technologies Research School, Nuclear Science and Technology Research Institute, North Kargar Avenue, P. O. Box 11365-8489, Tehran, Iran.
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2
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Orientation of Chiral Molecules by External Electric Fields: Focus on Photodissociation Dynamics. Symmetry (Basel) 2022. [DOI: 10.3390/sym14102152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Molecular orientation is a fundamental requirement to study and control photoinitiated reactions. Experimental setups that make use of hexapolar electric filters combined with slice-ion imaging detectors were employed in these last years to investigate the photodissociation dynamics of chiral molecules. The final goal is the on-the-fly discrimination of oriented enantiomers, revealed by the different angular distributions in photofragment ion-imaging, as predicted from vector correlation studies. Here, we review experiments of photodissociation of oriented chiral molecules, with the aim of presenting limits emerging from these investigations and perspectives toward the achievement of the ultimate objective.
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3
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Conformer Selection by Electrostatic Hexapoles: A Theoretical Study on 1-Chloroethanol and 2-Chloroethanol. Symmetry (Basel) 2022. [DOI: 10.3390/sym14020317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022] Open
Abstract
The electrostatic hexapole is a versatile device that has been used for many years in gas-phase experiments. Its inhomogeneous electric field has been employed for many purposes such as the selection of rotational states, the selection of clusters, the focusing of molecular beams, and molecular alignment as a precursor for molecular orientation. In the last few years, the hexapolar electric field has been demonstrated to be able to control the conformer composition of molecular beams. The key point is that conformers, where the component of the permanent electric dipole moment with respect to the largest of the principal axes of inertia is close to zero, require more intense hexapolar electric fields to be focused with respect to the other conformers. Here, we simulated the focusing curves of the conformers of 1-chloroethanol and 2-chloroethanol under hypothetical beam conditions, identical for all conformers, in a hypothetical and realistic experimental setup with three different hexapole lengths: 0.5, 1, and 2 m. The objective was to characterize this selection process to set up collision experiments on conformer-selected beams that provide information on the van der Waals clusters formed in collision processes.
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4
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Nautiyal VV, Devi S, Tyagi A, Vidhani B, Maan A, Prasad V. Orientation and Alignment dynamics of polar molecule driven by shaped laser pulses. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 256:119663. [PMID: 33827039 DOI: 10.1016/j.saa.2021.119663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/17/2021] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
We review the theoretical status of intense laser induced orientation and alignment-a field of study which lies at the interface of intense laser physics and chemical dynamics and having potential applications such as high harmonic generation, nano-scale processing and control of chemical reactions. The evolution of the rotational wave packet and its dynamics leading to orientation and alignment is the topic of the present discussion. The major part of this article primarily presents an overview of recent theoretical progress in controlling the orientation and alignment dynamics of a molecule by means of shaped laser pulses. The various theoretical approaches that lead to orientation and alignment such as static electrostatic field in combination with laser field(s), combination of orienting and aligning field, combination of aligning fields, combination of orienting fields, application of train of pulses etc. are discussed. It is observed that the train of pulses is quite an efficient tool for increasing the orientation or alignment of a molecule without causing the molecule to ionize. The orientation and alignment both can occur in adiabatic and non-adiabatic conditions with the rotational period of the molecule taken under consideration. The discussion is mostly limited to non-adiabatic rotational excitation (NAREX) i.e. cases in which the pulse duration is shorter than the rotational period of the molecule. We have emphasised on the so called half-cycle pulse (HCP) and square pulse (SQP). The effect of ramped pulses and of collision on the various laser parameters is also studied. We summarize the current discussion by presenting a consistent theoretical approach for describing the action of such pulses on movement of molecules. The impact of a particular pulse shape on the post-pulse dynamics is also calculated and analysed. In addition to this, the roles played by various laser parameters including the laser frequency, the pulse duration and the system temperature etc. are illustrated and discussed. The concept of alignment is extended from one-dimensional alignment to three-dimensional alignment with the proper choice of molecule and the polarised light. We conclude the article by discussing the potential applications of intense laser orientation and alignment.
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Affiliation(s)
- Vijit V Nautiyal
- Department of Physics and Astrophysics, University of Delhi, Delhi, Delhi 110007, India
| | - Sumana Devi
- Department of Physics and Astrophysics, University of Delhi, Delhi, Delhi 110007, India; Department of Physics, Miranda House College, University of Delhi, Delhi, Delhi 110007, India
| | - Ashish Tyagi
- Department of Physics, Swami Shradhanand College, University of Delhi, Delhi, Delhi 110036, India
| | - Bhavna Vidhani
- Department of Physics, Hansraj College, University of Delhi, Delhi, Delhi 110007, India
| | - Anjali Maan
- Department of Physics, Pt.N.R.S.G.C.Rohtak, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Vinod Prasad
- Department of Physics, Swami Shradhanand College, University of Delhi, Delhi, Delhi 110036, India.
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5
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Cheng QY, Song YZ, Meng QT. Field-free alignment of triatomic molecules controlled by a slow turn-on and rapid turn-off shaped laser pulse. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1859147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Qi-Yuan Cheng
- Medical Engineering Department, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, People’s Republic of China
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
- Shandong Laibo Biotechnology Co., Ltd., Jinan, People’s Republic of China
- School of Control Science and Engineering, Shandong University, Jinan, People’s Republic of China
| | - Yu-Zhi Song
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
| | - Qing-Tian Meng
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
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6
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Nakamura M, Palazzetti F, Tsai PY, Yang SJ, Lin KC, Kasai T, Che DC, Lombardi A, Aquilanti V. Vectorial imaging of the photodissociation of 2-bromobutane oriented via hexapolar state selection. Phys Chem Chem Phys 2019; 21:14164-14172. [PMID: 30350830 DOI: 10.1039/c8cp04270e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular orientation techniques are becoming available in the study of elementary chemical processes, in order to highlight those structural and dynamical properties that would be concealed by random rotational motions. Recently successful orientation was achieved for asymmetric-top and chiral molecules of much larger complexity than hitherto. In this work, we report and discuss the correlation between the vectors' photofragment recoil velocity v, transition dipole moment μ, and permanent dipole moment d in a dissociation experiment on hexapole oriented 2-bromobutane, photoinitiated by a linearly polarized laser. The sliced ion images of the Br*(2P1/2) and Br(2P3/2) photofragments were acquired at 234.0 and 254.1 nm, respectively, by a (2 + 1) resonance-enhanced multiphoton ionization technique. A detailed analysis of the sliced ion images obtained at a tilting angle 45° of laser polarization provides information on the correlation of the three vectors, which are confined by two polar angles α and χ and one azimuthal angle φμd in the recoil frame. The sliced ion images of Br fragments eliminated individually from the enantiomers at 254.1 nm yield an asymmetric factor close to zero; for this reason the photofragment angular distributions do not show significant differences. The elimination of the Br* fragment at 234.0 nm is mainly correlated with a parallel transition, giving rise to a large anisotropy parameter of 1.85, and thus can be considered as a single state excitation. The resulting recoil frame angles are optimized to 163° ± 8° and 164° ± 1° for α and χ, respectively, whereas φμd is approaching 0° for the best fit. Since for the present molecule, the three vectors have an only slight spatial arrangement, the photofragment angular distributions of the two enantiomers do not show appreciable differences. Theoretical and computational simulations provide us the basis to state that oriented enantiomers can be discriminated on-the-fly in photodissociation processes even initiated by non-circularly polarized light, provided that the three vectors encountered above have specific three-dimensional arrangements. The fact that Br fragment elimination involves a multi-potential dissociation carries uncertainties in theoretical estimates of the vector direction. Therefore, this work represents a preliminary but significant step on the road to chiral discrimination on-the-fly, which is shown to be best propitiated in molecules where vectors are far from having degenerate mutual angular directions.
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Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
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7
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Nakamura M, Yang SJ, Lin KC, Kasai T, Che DC, Lombardi A, Palazzetti F, Aquilanti V. Stereodirectional images of molecules oriented by a variable-voltage hexapolar field: Fragmentation channels of 2-bromobutane electronically excited at two photolysis wavelengths. J Chem Phys 2017; 147:013917. [DOI: 10.1063/1.4981025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Shiun-Jr Yang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Dock-Chil Che
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Andrea Lombardi
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
| | - Federico Palazzetti
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, 00016 Rome, Italy
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8
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Tsai PY. On the state selection of linear triatomic molecules by electrostatic hexapole fields. J Chem Phys 2016; 145:104311. [PMID: 27634264 DOI: 10.1063/1.4962359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Electrostatic hexapole state-selector is a versatile tool in experimental stereodynamics. The requirement of appropriate models to correctly predict the behavior of molecules in the hexapole motivated us to realize a treatment that predicts the Stark effect of linear triatomic molecules with rotational doublet states. Various perturbative approximations are conventionally adopted to obtain analytic Stark energy derivatives of a truncated Hamiltonian matrix, without utilizing numerical diagonalization of the full Hamiltonian matrix. By including both the low and high field effects, which were alternatively ignored in the analytical formulae of such approximate approaches, herein we demonstrate that the performance of hexapole state selector to linear triatomic molecules can be appropriately predicted via Van Vleck transformation. This method can provide analytic Stark energy derivatives that are acceptably in consistent with the ones obtained via numerical diagonalization of the full Hamiltonian matrix. Particularly, this work is suitable for v2 = 1 level of linear triatomic molecules, due to the following reasons: (1) the Stark energy derivative and the molecular orientation as a function of the electric field are expressed in analytical formulae, hence it is suitable for implementation without involving numerical diagonalization of the full Hamiltonian matrix; (2) a better prediction of the focusing curves with respect to conventional analytical treatments is provided, allowing a reliable determination of the selected state compositions and molecular orientation.
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Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan
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9
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Nakamura M, Yang SJ, Tsai PY, Kasai T, Lin KC, Che DC, Lombardi A, Palazzetti F, Aquilanti V. Hexapole-Oriented Asymmetric-Top Molecules and Their Stereodirectional Photodissociation Dynamics. J Phys Chem A 2016; 120:5389-98. [PMID: 27139246 DOI: 10.1021/acs.jpca.6b02410] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular orientation is a fundamental requisite in the study of stereodirected dynamics of collisional and photoinitiated processes. In this past decade, variable hexapolar electric filters have been developed and employed for the rotational-state selection and the alignment of molecules of increasing complexity, for which the main difficulties are their mass, their low symmetry, and the very dense rotational manifold. In this work, for the first time, a complex molecule such as 2-bromobutane, an asymmetric top containing a heavy atom (the bromine), was successfully oriented by a weak homogeneous field placed downstream from the hexapolar filter. Efficiency of the orientation was characterized experimentally, by combining time-of-flight measurements and a slice-ion-imaging detection technique. The application is described to the photodissociation dynamics of the oriented 2-bromobutane, which was carried out at a laser wavelength of 234 nm, corresponding to the breaking of the C-Br bond. The Br photofragment is produced in both the ground Br ((2)P3/2) and the excited Br ((2)P1/2) electronic states, and both channels are studied by the slice imaging technique, revealing new features in the velocity and angular distributions with respect to previous investigations on nonoriented molecules.
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Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University , Taipei, Taiwan
| | - Shiun-Jr Yang
- Department of Chemistry, National Taiwan University , Taipei, Taiwan
| | - Po-Yu Tsai
- Department of Chemistry, National Taiwan University , Taipei, Taiwan.,Department of Chemistry, National Chung-Hsing University , Taichung, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University , Taipei, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University , Taipei, Taiwan.,Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei, Taiwan
| | - Dock-Chil Che
- Graduate School of Science, Department of Chemistry, Osaka University , Osaka, Japan
| | - Andrea Lombardi
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Perugia, Italy
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Perugia, Italy.,Scuola Normale Superiore , Pisa, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Perugia, Italy.,Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia , 00016 Roma, Italy.,Insituto de Fìsica, Universidade Federal da Bahia , Salvador, Brazil
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10
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Palazzetti F, Maciel GS, Kanda K, Nakamura M, Che DC, Kasai T, Aquilanti V. Control of conformers combining cooling by supersonic expansion of seeded molecular beams with hexapole selection and alignment: experiment and theory on 2-butanol. Phys Chem Chem Phys 2014; 16:9866-75. [PMID: 24413635 DOI: 10.1039/c3cp54475c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selection and alignment of rotamers and, more in general, of conformers in the gas phase is a challenge that we tackle experimentally by supersonic expansion of seeded molecular beams and hexapolar electrostatic fields with quadrupole mass detection. The studied system involves the nine conformers of the asymmetric-top molecule 2-butanol, which coexist because of nearly free rotations around a CC and a CO bond. From the measured time-of-flight of a 2-butanol supersonic molecular beam seeded in either He or Ar, the corresponding velocity distributions are obtained. The different nature and masses of the seeding gas decrease selectively the vibrational temperature and determine the population of the conformers, which is assessed on the basis of their statistical distribution, derived from high level accompanying quantum mechanical calculations. The use of a hexapolar electrostatic field permits us to induce a variation of the population distribution as a function of the applied voltage and of the selective focusing and alignment of the conformers. A technique, recently developed for treating asymmetric tops and involving extensive trajectory simulations, is applied to obtain the link between the focusing curves, i.e. the dependence of the beam intensity on the hexapole voltage, and the conformers' populations and alignment. Perspectives are provided for photo- and stereo-dynamics experiments, particularly appealing also on account that 2-butanol is the simplest chiral alcohol.
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11
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Krupp AT, Gaj A, Balewski JB, Ilzhöfer P, Hofferberth S, Löw R, Pfau T, Kurz M, Schmelcher P. Alignment of D-state Rydberg molecules. PHYSICAL REVIEW LETTERS 2014; 112:143008. [PMID: 24765956 DOI: 10.1103/physrevlett.112.143008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Indexed: 06/03/2023]
Abstract
We report on the formation of ultralong-range Rydberg D-state molecules via photoassociation in an ultracold cloud of rubidium atoms. By applying a magnetic offset field on the order of 10 G and high resolution spectroscopy, we are able to resolve individual rovibrational molecular states. A full theory, using a Fermi pseudopotential approach including s- and p-wave scattering terms, reproduces the measured binding energies. The calculated molecular wave functions show that in the experiment we can selectively excite stationary molecular states with an extraordinary degree of alignment or antialignment with respect to the magnetic field axis.
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Affiliation(s)
- A T Krupp
- 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - A Gaj
- 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - J B Balewski
- 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - P Ilzhöfer
- 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - S Hofferberth
- 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - R Löw
- 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - T Pfau
- 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - M Kurz
- Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany and The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - P Schmelcher
- Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany and The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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12
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Roeterdink W, Bulthuis J, Lee E, Ding D, Taatjes C. Hexapole transmission spectrum of formaldehyde oxide. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Kasai T, Che DC, Okada M, Tsai PY, Lin KC, Palazzetti F, Aquilanti V. Directions of chemical change: experimental characterization of the stereodynamics of photodissociation and reactive processes. Phys Chem Chem Phys 2014; 16:9776-90. [DOI: 10.1039/c4cp00464g] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Kirste M, Haak H, Meijer G, van de Meerakker SYT. A compact hexapole state-selector for NO radicals. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:073113. [PMID: 23902050 DOI: 10.1063/1.4812267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Focusing of molecular beams using an electrostatic hexapole is a mature technique to produce samples of state-selected molecules. The ability to efficiently focus molecules depends on the properties of the molecular species of interest, the length of the hexapole state selector, as well as on the maximum electric field strength that can be achieved in these devices. In particular for species with a small effective dipole moment such as nitric oxide (NO), hexapole state selectors of several meters in length are required to focus the beam. We report on a novel design for an electrostatic hexapole state-selector that allows for a maximum electric field strength of 260 kV/cm, reducing significantly the length of the hexapole that is required to focus the beam. We demonstrate the focusing of a molecular beam of NO radicals (X (2)Π1∕2, v = 0, J = 1∕2, f) using a hexapole of only 30 cm length. A beamstop is integrated inside the hexapole at the geometric center of the device where the molecular trajectories have the largest deviation from the beam axis, effectively blocking the carrier gas of the molecular beam at minimum loss of NO density. The performance of the hexapole state-selector is investigated by state-selective laser induced fluorescence detection, as well as by two-dimensional imaging of the focused packet of NO radicals. The resulting packet of NO radicals has a density of 9 ± 3 × 10(10) cm(-3) and a state purity of 99%.
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Affiliation(s)
- Moritz Kirste
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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15
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Schäfer T, Bartels N, Hocke N, Yang X, Wodtke AM. Orienting polar molecules without hexapoles: Optical state selection with adiabatic orientation. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.03.056] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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16
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Electrostatic hexapole state-selection of the asymmetric-top molecule propylene oxide: Rotational and orientational distributions. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.11.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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17
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van de Meerakker SYT, Bethlem HL, Vanhaecke N, Meijer G. Manipulation and Control of Molecular Beams. Chem Rev 2012; 112:4828-78. [DOI: 10.1021/cr200349r] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Hendrick L. Bethlem
- Institute for Lasers, Life and
Biophotonics, VU University Amsterdam,
De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Nicolas Vanhaecke
- Laboratoire Aimé Cotton, CNRS, Bâtiment 505, Université Paris-Sud,
91405 Orsay, France
| | - Gerard Meijer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin,
Germany
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18
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Omiste JJ, González-Férez R, Schmelcher P. Rotational spectrum of asymmetric top molecules in combined static and laser fields. J Chem Phys 2011; 135:064310. [DOI: 10.1063/1.3624774] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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19
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Abstract
Process intensification follows four main goals: to maximize the effectiveness of intra- and intermolecular events, to give each molecule the same processing experience, to optimize the driving forces/maximize specific interfacial areas, and to maximize the synergistic effects of partial processes. This paper shows how these goals can be reached in reaction and separation systems at all relevant time and length scales and is focused on the structuring of reactors and separation units, on the use of different energy forms to improve the reaction and separation, on combining and superimposing of different phenomena in one integrated unit or reactor, and on the application of oscillations for intensification of reaction and separation processes.
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Affiliation(s)
- Andrzej Górak
- Department of Biochemical and Chemical Engineering, Laboratory of Fluid Separations, Dortmund University of Technology, 44227 Dortmund, Germany
- Department of Process and Environmental Engineering, Lodz University of Technology, 90924 Lodz, Poland
| | - Andrzej Stankiewicz
- Process and Energy Department, Intensified Reaction and Separation Systems, Delft University of Technology, 2628 CA Delft, The Netherlands
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20
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Che DC, Palazzetti F, Okuno Y, Aquilanti V, Kasai T. Electrostatic hexapole state-selection of the asymmetric-top molecule propylene oxide. J Phys Chem A 2010; 114:3280-6. [PMID: 20099859 DOI: 10.1021/jp909553t] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rotational state-selection of the asymmetric-top molecule propylene oxide was carried out using an electrostatic hexapole field of 85-cm length. Molecular beam intensities were monitored by a quadrupole mass spectrometer. It was found that beam intensities of molecular beams for pure propylene oxide and those seeded in He and in Ar increased with increasing hexapole voltages. The hexapole voltage dependence of the beam intensity, which is called the focusing curve, was interpreted by computer simulation of the trajectories of molecules in the hexapolar field due to the Stark effect, as a function of rotational temperatures of molecular beams. The calculated best fit focusing curves, when compared with the experimental results, demonstrated that the rotational temperatures, associated with the distribution of states of a given rotational angular momentum J, are similar to the translational temperatures. It was found that the M = 0 states (where M is the projection of J along the direction of the electrostatic field) and negative values of the pseudoquantum number tau of propylene oxide can be selected using our experimental setup. These results suggest that the hexapole electric field is a tool even for the selection of rotational and orientation states of asymmetric-top molecules.
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Affiliation(s)
- Dock-Chil Che
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
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Liu Y, Yun M, Xia Y, Deng L, Yin J. Experimental generation of a cw cold CH3CN molecular beam by a low-pass energy filtering. Phys Chem Chem Phys 2010; 12:745-52. [DOI: 10.1039/b913929j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Elghobashi-Meinhardt N, González L, Barth I, Seideman T. Few-cycle laser pulses to obtain spatial separation of OHF− dissociation products. J Chem Phys 2009; 130:024310. [DOI: 10.1063/1.3054276] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Xia Y, Yin Y, Chen H, Deng L, Yin J. Quadrupolelike electrostatic guiding for cold polar molecules. J Chem Phys 2008; 128:094301. [DOI: 10.1063/1.2837462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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D'Andrea TM, Zhang X, Jochnowitz EB, Lindeman TG, Simpson CJSM, David DE, Curtiss TJ, Morris JR, Ellison GB. Oxidation of Organic Films by Beams of Hydroxyl Radicals. J Phys Chem B 2007; 112:535-44. [DOI: 10.1021/jp7096108] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Timothy M. D'Andrea
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - Xu Zhang
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - Evan B. Jochnowitz
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - T. G. Lindeman
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - C. J. S. M. Simpson
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - Donald E. David
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - Thomas J. Curtiss
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - John R. Morris
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - G. Barney Ellison
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
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Bhattacharya M, Raman C. Detecting level crossings without looking at the spectrum. PHYSICAL REVIEW LETTERS 2006; 97:140405. [PMID: 17155226 DOI: 10.1103/physrevlett.97.140405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Indexed: 05/12/2023]
Abstract
In many physical systems it is important to be aware of the crossings and avoided crossings which occur when eigenvalues of a physical observable are varied using an external parameter. We have discovered a powerful algebraic method of finding such crossings via a mapping to the problem of locating the roots of a polynomial in that parameter. We demonstrate our method on atoms and molecules in a magnetic field, where it has implications in the search for Feshbach resonances. In the atomic case our method allows us to point out a new class of invariants of the Breit-Rabi Hamiltonian of magnetic resonance. In the case of molecules, it enables us to find curve crossings with practically no knowledge of the corresponding Born-Oppenheimer potentials.
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Affiliation(s)
- M Bhattacharya
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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Schwettmann A, Franklin J, Overstreet KR, Shaffer JP. Stark slowing asymmetric rotors: weak-field-seeking states and nonadiabatic transitions. J Chem Phys 2005; 123:194305. [PMID: 16321086 DOI: 10.1063/1.2112787] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Stark deceleration is one of the few methods that can be used to slow polyatomic molecules. We present calculations of Stark shift energies, a quantitative analysis of nonadiabatic transition probabilities, and orientational distribution functions applicable to typical Stark slowing conditions for the two small asymmetric rotors nitromethane and acetaldehyde. We show that asymmetric polyatomic molecules are good candidates for Stark slowing.
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Affiliation(s)
- Arne Schwettmann
- The University of Oklahoma, Homer L. Dodge Department of Physics and Astronomy, Norman, OK 73019, USA
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Guérin S, Yatsenko LP, Jauslin HR, Faucher O, Lavorel B. Orientation of polar molecules by laser induced adiabatic passage. PHYSICAL REVIEW LETTERS 2002; 88:233601. [PMID: 12059362 DOI: 10.1103/physrevlett.88.233601] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2001] [Indexed: 05/23/2023]
Abstract
We show that two overlapping linearly polarized laser pulses of frequencies omega and its second harmonic 2omega can strongly orient linear polar molecules, by adiabatic passage along dressed states. The resulting robust orientation can be interpreted as a laser-induced localization in the effective double well potential created by the fields, which induces a preliminary molecular alignment. The direction of the orientation can be selected by the relative phase of the fields.
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Affiliation(s)
- S Guérin
- Laboratoire de Physique de l'Université de Bourgogne, UMR CNRS 5027, BP 47870, 21078 Dijon, France.
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Okano A, Ohoyama H, Kasai T. Focusing and selecting the linear type HBr–N2O by using a 2 m long electrostatic hexapole field. J Chem Phys 2002. [DOI: 10.1063/1.1429954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bowman JM, Irle S, Morokuma K, Wodtke A. Dipole moments of highly vibrationally excited HCN: Theoretical prediction of an experimental diagnostic for delocalized states. J Chem Phys 2001. [DOI: 10.1063/1.1364681] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Silva M, Jongma R, Field RW, Wodtke AM. The dynamics of "stretched molecules": experimental studies of highly vibrationally excited molecules with stimulated emission pumping. Annu Rev Phys Chem 2001; 52:811-52. [PMID: 11326081 DOI: 10.1146/annurev.physchem.52.1.811] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We review stimulated emission pumping as used to study molecular dynamics. The review presents unimolecular as well as scattering studies. Topics include intramolecular vibrational redistribution, unimolecular isomerization and dissociation, van der Waals clusters, rotational energy transfer, vibrational energy transfer, gas-surface interactions, atmospheric effects resulting from nonequilibrium vibrational excitation, and vibrational promotion of electron transfer.
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Affiliation(s)
- M Silva
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA.
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