Stimulated Emission Pumping: New Methods in Spectroscopy and Molecular Dynamics

Hamilton, C. E.; Kinsey, James L.; Field, Robert W.

doi:10.1146/annurev.pc.37.100186.002425

Cited by 346 publications

(104 citation statements)

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“…Many Lanczos runs must be performed in order to statistically converge the elements of the density correlation matrix D. Hence, even though basis sets extending to tens of millions are manageable if one only requires a small number of Lanczos runs, the compute time associated with the matrix-vector multiply operation will become a severe bottleneck for the density correlation method. Given current hardware, this puts a practical limit on the basis set size of around 10 5 -10 6 . With these limits in mind, we suggest the algorithm should be applicable to molecular systems in the energy range where the total sum of states does not exceed about 10 5 .…”

Section: Discussionmentioning

confidence: 99%

“…This causes the expected zeroth order spectrum to split and enables high resolution spectroscopy to provide experimental estimates for the absolute state densities. [6][7][8][9] Third, local mode behavior can develop as a result of dynamical resonances embedded within generally nonseparable ͑or, mixed͒ eigenfunctions. 10 Fourth, as separability breaks down, eigenfunctions may lose essentially all resemblance to their zeroth order counterparts, such that spectral assignment based on a zeroth order Hamiltonian becomes impossible.…”

Section: Introductionmentioning

confidence: 99%

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On the calculation of absolute spectral densities

Smith

Jeffrey

1996

The Journal of Chemical Physics

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On the relation of protein dynamics and exciton relaxation in pigment-protein complexes: An estimation of the spectral density and a theory for the calculation of optical spectra J. Chem. Phys. 116, 9997 (2002) A new method of calculating the absolute spectral density of a Hamiltonian operator is derived and discussed. The spectral density is expressed as the solution of an integral equation in which the kernel is a renormalized one-sided energy correlation function of the full microcanonical density operator and a microcanonical density operator for a reference Hamiltonian. The integral operator associated with this equation transforms a known spectral density function for the reference Hamiltonian into the spectral density of the full Hamiltonian. The integral equation, by virtue of its formulation in energy space, is inherently one-dimensional and offers no storage difficulties, and the elements of its kernel may be computed by applying the Lanczos algorithm to randomly selected eigenfunctions of the reference Hamiltonian. This spectral density correlation method offers a number of advantages over variational methods. In particular, it has the potential for overcoming the hitherto largely insurmountable problem of tracing over a multidimensional Hilbert space in order to compute the spectral density of a nonseparable molecular Hamiltonian.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the calculation of absolute spectral densities

Smith

Jeffrey

1996

The Journal of Chemical Physics

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“…A good example of an application that is rather demanding in this regard is stimulated emission pumping ͑SEP͒. 47,[54][55][56][57][58][59][60][61] SEP is a folded variant of opticaloptical double resonance that is particularly sensitive to wavelength instability due to the fact that the ⌳ transition is carried out between 2 ms or longer-lived vibrational states of the ground electronic state, whose natural linewidth is less than 1 kHz. Here a PUMP laser excites a molecule to a single rotational level of an excited electronic state and a second DUMP laser is used to stimulate emission transferring population back to a vibrationally excited level in the ground electronic state.…”

Section: A Applications To High Resolution Spectroscopy and Optical mentioning

confidence: 99%

Generation of tunable narrow bandwidth nanosecond pulses in the deep ultraviolet for efficient optical pumping and high resolution spectroscopy

Velarde

Engelhart

Matsiev

et al. 2010

Review of Scientific Instruments

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Generation of programmable near-Fourier-transform-limited pulses of narrow-band laser radiation from the near infrared to the vacuum ultraviolet Rev. Sci. Instrum. 76, 103103 (2005) Nanosecond optical pulses with high power and spectral brightness in the deep ultraviolet ͑UV͒ region have been produced by sum frequency mixing of nearly transform-limited-bandwidth IR light originating from a home-built injection-seeded ring cavity KTiOPO 4 optical parametric oscillator ͑OPO͒ and the fourth harmonic beam of an injection-seeded Nd:YAG laser used simultaneously to pump the OPO with the second harmonic. We demonstrate UV output, tunable from 204 to 207 nm, which exhibits pulse energies up to 5 mJ with a bandwidth better than 0.01 cm −1 . We describe how the approach shown in this paper can be extended to wavelengths shorter than 185 nm. The injection-seeded OPO provides high conversion efficiency ͑Ͼ40% overall energy conversion͒ and superior beam quality required for highly efficient downstream mixing where sum frequencies are generated in the UV. The frequency stability of the system is excellent, making it highly suitable for optical pumping. We demonstrate high resolution spectroscopy as well as optical pumping using laser-induced fluorescence and stimulated emission pumping, respectively, in supersonic pulsed molecular beams of nitric oxide.

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“…16,17 In this work we have performed experiments on highly vibrationally excited NO, prepared by stimulated emission pumping, 18 to study near resonant V-V energy transfer to N 2 O under single-collision, single-initialquantum-state conditions. We observe a change in the rotational distribution of the vibrationally inelastic channel for scattered NO which suggests that most, if not all, of the energy defect is compensated by NO rotation.…”

Section: Introductionmentioning

confidence: 99%

Rotational motion compensates the energy defect in near-resonant vibration–vibration energy transfer: A state-to-state study of NO(v)+N2O

Drabbels

Wodtke

1998

The Journal of Chemical Physics

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Our lack of understanding of the factors that compensate energy defects in near resonant V-V energy transfer constrains our ability to accurately predict resonance widths and, thus, the overall importance of such processes. We have carried out one of the first truly state-to-state measurements of near resonant V-V energy transfer under single collision conditions, employing the crossed molecular beams, stimulated emission pumping technique. We have varied the energy defect ⌬E for the process: NO X 2 ⌸(v)ϩN 2 O(0,0,0)→NO X 2 ⌸(vϪ1)ϩN 2 O(0,0,1), by changing the prepared vibrational state from vϭ22 (⌬Eϭϩ14 cm Ϫ1 ) to vϭ21 (⌬EϭϪ18 cm Ϫ1 ) to vϭ20 (⌬EϭϪ49 cm Ϫ1 ). Changes in the energy transfer efficiencies and rotational distributions of vibrationally inelastically scattered NO with energy defect both strongly suggest that molecular rotation ͑both of NO and N 2 O͒ is responsible for compensating the energy defect. Furthermore it appears that relative translation is ineffective in compensating the energy defect. A ⌬J NO ϳ⌬J N 2 0 approximation also appears valid.

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Stimulated Emission Pumping: New Methods in Spectroscopy and Molecular Dynamics

Cited by 346 publications

References 0 publications

On the calculation of absolute spectral densities

On the calculation of absolute spectral densities

Generation of tunable narrow bandwidth nanosecond pulses in the deep ultraviolet for efficient optical pumping and high resolution spectroscopy

Rotational motion compensates the energy defect in near-resonant vibration–vibration energy transfer: A state-to-state study of NO(v)+N2O

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