Bond selective infrared multiphoton excitation and dissociation of linear monodeuterated acetylene

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.471907· OSTI ID:285552

Kaluza, M; Muckerman, J T ^[1]

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1. Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

Quantum mechanical simulations of vibrational excitation of monodeuterated linear acetylene (HCCD) with linearly polarized, frequency-swept, intense but nonionizing infrared laser pulses are performed. The aim is selective dissociation of either H or D atoms by optimal shaping of the laser pulses. We use a discrete variable representation and a compact ({lt}400 states) bright-state expansion to represent the wave function during and after the pulse. Wave packet propagations in the bright-state expansion are at least an order of magnitude faster than discrete variable representation wave packet propagations. This enables optimal-control calculations to find the best parameters for the laser pulses. The dynamics of CH-bond breaking with infrared pulses are very different from the dynamics of CD-bond breaking. This is a direct consequence of CH being the highest-frequency mode in the molecule. Selective CH-bond breaking is possible with two synchronized pulses, the first being quasi-resonant with the {Delta}{ital v}=1 transitions in the CH stretch between {ital v}=0 and {ital v}=8, and the second being quasiresonant with {Delta}{ital v}=2 transitions at higher {ital v}. H-atom yields as high as 7.7{percent}, with H to D yield ratio as high as 2.1, are demonstrated. Selective CD-bond breaking is possible using a single, subpicosecond, frequency-swept pulse. D-atom yields as high as 3{percent}, or D to H atom yield ratios as high as 3.9, are calculated. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: Brookhaven National Laboratory
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 285552
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 2 Vol. 105; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ACETYLENE
ALKYNES
CHEMICAL BONDS
CONTROL
DISSOCIATION
ELECTROMAGNETIC PULSES
EXCITATION
INFRARED RADIATION
LASER RADIATION
MULTI-PHOTON PROCESSES
PHOTOCHEMICAL REACTIONS
PHOTODISSOCIATION
SIMULATION
VIBRATIONAL STATES