Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

The Journal of Chemical Physics

Counterintuitive multiphoton pulse sequences in molecular isomerization. I. Selectivity and robustness of competing multiphoton stimulated Raman adiabatic passage processes

Imrich Vrábel, Werner Jakubetz

Published Apr 11, 2003• 28 citations
Publisher

Abstract

We use a 28-level system consisting of the vibrational bend states of the HCN/HNC system as a model system for the investigation of population transfer across the isomerization barrier using counterintuitively ordered multiphoton (MP) laser pulses. This (m+n)-STIRAP (stimulated Raman-adiabatic passage) arrangement with m pump- and n Stokes-photons is found to be capable of driving HCN→HNC transition states selectively and in a robust manner, despite the presence of near-degenerate parallel processes of different photonicities. Employing Gaussian pulses with widths of 80 ps, the process of highest photonicity we demonstrate is (4+6)-STIRAP, and we investigate systematically the robustness against variations in pulse amplitudes and frequencies for all parallel processes with m=2 and 3, and n=1–6. We discuss the conditions under which selective population transfer is obtained. We also compare with (1+1)-STIRAP using overtone transitions to drive the same state-specific processes and conclude that the few-step sequential MP-STIRAP isomerization is a feasible alternative to the sequential (1+1)-STIRAP based method proposed by Kurkal and Rice [J. Phys. Chem. B 105, 6488 (2001)].

DOI
10.1063/1.1545773

Related papers

Selective Vibrational Population Transfer using Combined Stimulated Raman Adiabatic Passage and Counter-Diabatic Fields

Shumpei Masuda, Stuart A. Rice

We report studies of state-to-state vibrational energy transfer in an isolated polyatomic molecule driven by combined stimulated Raman adiabatic passage (STIRAP) and counter-diabatic fields (CDFs). The goal of these studies is development of a method for improving the efficiency of level-to-level population transfer under conditions that degrade the efficiency of conventional STIRAP-generated population transfer. The vehicles for our studies are selective population of one of a pair of near-degenerate states in nonrotating SCCl 2 and enhancing the yield of nonrotating HNC in the HCN → HNC isomerization reaction. The efficiency of the population transfer within a subset of states embedded in a manifold of states is examined for the cases in which the transition dipole moments between the initial and target states are much smaller than and comparable to the transition dipole moments between background states and for the case in which the subset states have large transition dipole moments with the background states. We show that, in a subset of states that is coupled to background states, a combination of STIRAP fields and CDFs that do not individually generate processes that are competitive with the desired population transfer can generate population transfer efficiency greater than can ordinary STIRAP with field strength and/or pulse duration similarly restricted and that the exact CDF for an isolated three-level system is a useful approximation to the exact CDF for three- and five-state systems embedded in background states. We report a study of the stability of the STIRAP and approximate CDF control protocol to variation of the CDF intensity, the relative phase between the STIRAP and CDFs, and the pulse duration.

The Journal of Physical Chemistry C•Oct 27, 2014•24 citations

Selective Vibrational Population Transfer using Combined STIRAP and Counter-Diabatic Fields

Shumpei Masuda, Stuart A. Rice

We report studies of state-to-state vibrational energy transfer in an isolated polyatomic molecule driven by combined stimulated Raman adiabatic passage (STIRAP) and counter-diabatic fields (CDF), using as vehicles selective population of one of a pair of near degenerate states in SCCl$_2$ and enhancing the yield of HNC in the HCN/HNC isomerization reaction. The efficiency of the population transfer within a subset of states embedded in a dense manifold of states is examined for the cases that the transition dipole moments between the initial and target states are much smaller than and comparable to the transition dipole moments between background states, and for the case that the subset states have large transition dipole moments with the background states. We show that, in a subset of states that is coupled to background states, a combination of STIRAP fields and CDFs that do not individually generate processes that are competitive with the desired population transfer can generate greater population transfer efficiency than can ordinary STIRAP with field strength and/or pulse duration similarly restricted. We also show that the exact CDF for an isolated three level system is a useful approximation to the exact CDF for three and five state systems embedded in background states, and we report a study of the stability of the STIRAP + approximate CDF control protocol to variation of the CDF.

arXiv:1409.0784•Sep 2, 2014•2 citations

Limitations of STIRAP-like population transfer in extended systems: The three-level system embedded in a web of background states

Werner Jakubetz

This paper presents a systematic numerical investigation of background state participation in STIRAP (stimulated Raman-adiabatic passage) population transfer among vibrational states, focusing on the consequences for the robustness of the method. The simulations, which are performed over extended grids in the parameter space of the Stokes- and pump pulses (frequencies, field strengths, and pulse lengths), involve hierarchies of (3 + N)-level systems of increasing complexity, ranging from the standard three-level STIRAP setup, (N = 0) in Λ-configuration, up to N = 446. A strongly coupled three-level core system is selected from the full Hamiltonian of the double-well HCN∕HNC system, and the couplings connecting this core system to the remaining states are (re-) parameterized in different ways, from very weak to very strong. The systems so obtained represent a three-level system embedded in various ways in webs of cross-linked vibrational background states and incorporate typical molecular properties. We first summarize essential properties of population transfer in the standard three-level system and quantify the robustness of the method and its dependence on the pulse parameters. Against these reference results, we present results obtained for four (3 + 446)-level systems and several subsystems. For pulse lengths of at most few picoseconds the intrinsic robustness of STIRAP with respect to variations in the field strength disappears as soon as the largest core-background couplings exceed about one tenth of the STIRAP couplings. In such cases robustness with respect to variations in the field strength is entirely lost, since at higher field strengths, except for irregularly spaced narrow frequency ranges, transfer probabilities are strongly reduced. STIRAP-like population transfer is maintained, with some restrictions, at low field strengths near the onset of adiabatic transfer. The suppression of STIRAP is traced back to different mechanisms based on a plentitude of single- and multiphoton transitions to background states, which at the high field strengths characteristic for STIRAP proceed readily even along weakly coupled pathways.

The Journal of Chemical Physics•Dec 13, 2012•16 citations

Stimulated Raman adiabatic passage in molecules: The effects of background states

Taiwang Cheng, Hariyanto Darmawan, Alex Brown

The effects of a background state, or states, on stimulated Raman adiabatic passage (STIRAP) processes are investigated. The study is based on a realistic model of the laser-assisted $\mathrm{HCN}\ensuremath{\rightarrow}\mathrm{HNC}$ isomerization process. While the high density of states in the energy regime above the isomerization barrier plays an important role, the strong variation of the transition dipole moments connecting these states with the localized HCN and HNC states is shown to be more significant in determining the success or failure of the STIRAP process. Therefore, care must be taken when proposing the use of STIRAP-based schemes to control molecular excitation especially when control is justified via few-level models.

Physical Review A•Jan 11, 2007•16 citations

Simple and robust extension of the stimulated Raman adiabatic passage technique to N -level systems

Vladimir S. Malinovsky, David J. Tannor

STIRAP (stimulated Raman adiabatic passage) has proven to be an efficient and robust technique for transferring population in a three-level system without populating the intermediate state. Here we show that the counterintuitive pulse sequence in STIRAP, in which the Stokes pulse precedes the pump, emerges automatically from a variant of optimal control theory we have previously called ``local'' optimization. Since local optimization is a well-defined, automated computational procedure, this opens the door to automated computation of generalized STIRAP schemes in arbitrarily complicated $N$-level coupling situations. If the coupling is sequential, a simple qualitative extension of STIRAP emerges: the Stokes pulse precedes the pump as in the three-level system. But, in addition, spanning both the Stokes and pump pulses are pulses corresponding to the transitions between the $N\ensuremath{-}2$ intermediate states with intensities about an order of magnitude greater than those of the Stokes and pump pulses. This scheme is amazingly robust, leading to almost 100% population transfer with significantly less population transfer to the $N\ensuremath{-}2$ intermediate states than in previously proposed extensions of STIRAP.

Physical Review A•Dec 1, 1997•165 citations

Selective photochemistry via adiabatic passage: An extension of stimulated Raman adiabatic passage for degenerate final states

Mark N. Kobrak, Stuart A. Rice

In this paper we extend the existing theory of stimulated Raman adiabatic passage (StiRAP) in three-level systems to examine the nature of selective photoexcitation using counterintuitively ordered pulses. Our goal is to develop a version of StiRAP that permits control of product selectivity in a chemical reaction. We analyze the case of selective excitation to one state in a pair of degenerate target states in a four-level system, and find that one cannot control the ratio of the populations in the two states in a resonant two-photon process. However, the extension of the system to include a fifth state and a third laser field makes selective excitation to one of the degenerate states possible. It is found that, subject to reasonable restrictions, one may accomplish complete population transfer to a single target state of a degenerate pair of states in a five-level system.

Physical Review A•Apr 1, 1998•85 citations
We use a 28-level system consisting of the vibrational bend states of the HCN/HNC system as a model system for the investigation of population transfer across the isomerization barrier using counterintuitively ordered multiphoton (MP) laser pulses. This (m+n)-STIRAP (stimulated Raman-adiabatic passage) arrangement with m pump- and n Stokes-photons is found to be capable of driving HCN→HNC transition states selectively and in a robust manner, despite the presence of near-degenerate parallel processes of different photonicities. Employing Gaussian pulses with widths of 80 ps, the process of highest photonicity we demonstrate is (4+6)-STIRAP, and we investigate systematically the robustness against variations in pulse amplitudes and frequencies for all parallel processes with m=2 and 3, and n=1–6. We discuss the conditions under which selective population transfer is obtained. We also compare with (1+1)-STIRAP using overtone transitions to drive the same state-specific processes and conclude that the few-step sequential MP-STIRAP isomerization is a feasible alternative to the sequential (1+1)-STIRAP based method proposed by Kurkal and Rice [J. Phys. Chem. B 105, 6488 (2001)].
We report studies of state-to-state vibrational energy transfer in an isolated polyatomic molecule driven by combined stimulated Raman adiabatic passage (STIRAP) and counter-diabatic fields (CDFs). The goal of these studies is development of a method for improving the efficiency of level-to-level population transfer under conditions that degrade the efficiency of conventional STIRAP-generated population transfer. The vehicles for our studies are selective population of one of a pair of near-degenerate states in nonrotating SCCl 2 and enhancing the yield of nonrotating HNC in the HCN → HNC isomerization reaction. The efficiency of the population transfer within a subset of states embedded in a manifold of states is examined for the cases in which the transition dipole moments between the initial and target states are much smaller than and comparable to the transition dipole moments between background states and for the case in which the subset states have large transition dipole moments with the background states. We show that, in a subset of states that is coupled to background states, a combination of STIRAP fields and CDFs that do not individually generate processes that are competitive with the desired population transfer can generate population transfer efficiency greater than can ordinary STIRAP with field strength and/or pulse duration similarly restricted and that the exact CDF for an isolated three-level system is a useful approximation to the exact CDF for three- and five-state systems embedded in background states. We report a study of the stability of the STIRAP and approximate CDF control protocol to variation of the CDF intensity, the relative phase between the STIRAP and CDFs, and the pulse duration.
We report studies of state-to-state vibrational energy transfer in an isolated polyatomic molecule driven by combined stimulated Raman adiabatic passage (STIRAP) and counter-diabatic fields (CDF), using as vehicles selective population of one of a pair of near degenerate states in SCCl2_22​ and enhancing the yield of HNC in the HCN/HNC isomerization reaction. The efficiency of the population transfer within a subset of states embedded in a dense manifold of states is examined for the cases that the transition dipole moments between the initial and target states are much smaller than and comparable to the transition dipole moments between background states, and for the case that the subset states have large transition dipole moments with the background states. We show that, in a subset of states that is coupled to background states, a combination of STIRAP fields and CDFs that do not individually generate processes that are competitive with the desired population transfer can generate greater population transfer efficiency than can ordinary STIRAP with field strength and/or pulse duration similarly restricted. We also show that the exact CDF for an isolated three level system is a useful approximation to the exact CDF for three and five state systems embedded in background states, and we report a study of the stability of the STIRAP + approximate CDF control protocol to variation of the CDF.
This paper presents a systematic numerical investigation of background state participation in STIRAP (stimulated Raman-adiabatic passage) population transfer among vibrational states, focusing on the consequences for the robustness of the method. The simulations, which are performed over extended grids in the parameter space of the Stokes- and pump pulses (frequencies, field strengths, and pulse lengths), involve hierarchies of (3 + N)-level systems of increasing complexity, ranging from the standard three-level STIRAP setup, (N = 0) in Λ-configuration, up to N = 446. A strongly coupled three-level core system is selected from the full Hamiltonian of the double-well HCN∕HNC system, and the couplings connecting this core system to the remaining states are (re-) parameterized in different ways, from very weak to very strong. The systems so obtained represent a three-level system embedded in various ways in webs of cross-linked vibrational background states and incorporate typical molecular properties. We first summarize essential properties of population transfer in the standard three-level system and quantify the robustness of the method and its dependence on the pulse parameters. Against these reference results, we present results obtained for four (3 + 446)-level systems and several subsystems. For pulse lengths of at most few picoseconds the intrinsic robustness of STIRAP with respect to variations in the field strength disappears as soon as the largest core-background couplings exceed about one tenth of the STIRAP couplings. In such cases robustness with respect to variations in the field strength is entirely lost, since at higher field strengths, except for irregularly spaced narrow frequency ranges, transfer probabilities are strongly reduced. STIRAP-like population transfer is maintained, with some restrictions, at low field strengths near the onset of adiabatic transfer. The suppression of STIRAP is traced back to different mechanisms based on a plentitude of single- and multiphoton transitions to background states, which at the high field strengths characteristic for STIRAP proceed readily even along weakly coupled pathways.
The effects of a background state, or states, on stimulated Raman adiabatic passage (STIRAP) processes are investigated. The study is based on a realistic model of the laser-assisted $\mathrm{HCN}\ensuremath{\rightarrow}\mathrm{HNC}$ isomerization process. While the high density of states in the energy regime above the isomerization barrier plays an important role, the strong variation of the transition dipole moments connecting these states with the localized HCN and HNC states is shown to be more significant in determining the success or failure of the STIRAP process. Therefore, care must be taken when proposing the use of STIRAP-based schemes to control molecular excitation especially when control is justified via few-level models.
STIRAP (stimulated Raman adiabatic passage) has proven to be an efficient and robust technique for transferring population in a three-level system without populating the intermediate state. Here we show that the counterintuitive pulse sequence in STIRAP, in which the Stokes pulse precedes the pump, emerges automatically from a variant of optimal control theory we have previously called ``local'' optimization. Since local optimization is a well-defined, automated computational procedure, this opens the door to automated computation of generalized STIRAP schemes in arbitrarily complicated NNN-level coupling situations. If the coupling is sequential, a simple qualitative extension of STIRAP emerges: the Stokes pulse precedes the pump as in the three-level system. But, in addition, spanning both the Stokes and pump pulses are pulses corresponding to the transitions between the $N\ensuremath{-}2$ intermediate states with intensities about an order of magnitude greater than those of the Stokes and pump pulses. This scheme is amazingly robust, leading to almost 100% population transfer with significantly less population transfer to the $N\ensuremath{-}2$ intermediate states than in previously proposed extensions of STIRAP.
In this paper we extend the existing theory of stimulated Raman adiabatic passage (StiRAP) in three-level systems to examine the nature of selective photoexcitation using counterintuitively ordered pulses. Our goal is to develop a version of StiRAP that permits control of product selectivity in a chemical reaction. We analyze the case of selective excitation to one state in a pair of degenerate target states in a four-level system, and find that one cannot control the ratio of the populations in the two states in a resonant two-photon process. However, the extension of the system to include a fifth state and a third laser field makes selective excitation to one of the degenerate states possible. It is found that, subject to reasonable restrictions, one may accomplish complete population transfer to a single target state of a degenerate pair of states in a five-level system.