Threshold photoelectron spectroscopy of HBr and DBr

Yencha, Andrew J.; Cormack, A.J.; Donovan, Robert J.; Lawley, Kenneth P.; Hopkirk, A.; King, G C

doi:10.1016/s0301-0104(98)00280-8

Cited by 36 publications

(26 citation statements)

References 53 publications

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“…1-13͒ and HBr, [14][15][16][17][18][19] are perhaps the most studied diatomic molecules in the field of photodissociation and photoionization dynamics. 1-13͒ and HBr, [14][15][16][17][18][19] are perhaps the most studied diatomic molecules in the field of photodissociation and photoionization dynamics.…”

Section: Introductionmentioning

confidence: 99%

Proton formation in 2+1 resonance enhanced multiphoton excitation of HCl and HBr via (Ω=) Rydberg and ion-pair states

Romanescu

Loock

2007

The Journal of Chemical Physics

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Molecular beam cooled HCl was state selected by two-photon excitation of the V (1) summation operator(0(+)) [v=9,11-13,15], E (1) summation operator(0(+)) [v=0], and g (3) summation operator(-)(0(+)) [v=0] states through either the Q(0) or Q(1) lines of the respective (1,3) summation operator(0(+))<--<--X (1) summation operator(0(+)) transition. Similarly, HBr was excited to the V (1) summation operator(0(+)) [v=m+3, m+5-m+8], E (1) summation operator(0(+)) [v=0], and H (1) summation operator(0(+)) [v=0] states through the Q(0) or Q(1) lines. Following absorption of a third photon, protons were formed by three different mechanisms and detected using velocity map imaging. (1) H(*)(n=2) was formed in coincidence with (2)P(i) halogen atoms and subsequently ionized. For HCl, photodissociation into H(*)(n=2)+Cl((2)P(12)) was dominant over the formation of Cl((2)P(32)) and was attributed to parallel excitation of the repulsive [(2) (2)Pi4llambda] superexcited (Omega=0) states. For HBr, the Br((2)P(32))Br((2)P(12)) ratio decreases with increasing excitation energy. This indicates that both the [(3) (2)Pi(12)5llambda] and the [B (2) summation operator5llambda] superexcited (Omega=0) states contribute to the formation of H(*)(n=2). (2) For selected intermediate states HCl was found to dissociate into the H(+)+Cl(-) ion pair with over 20% relative yield. A mechanism is proposed by which a bound [A (2) summation operatornlsigma] (1) summation operator(0(+)) superexcited state acts as a gateway state to dissociation into the ion pair. (3) For all intermediate states, protons were formed by dissociation of HX(+)[v(+)] following a parallel, DeltaOmega=0, excitation. The quantum yield for the dissociation process was obtained using previously reported photoionization efficiency data and was found to peak at v(+)=6-7 for HCl and v(+)=12 for HBr. This is consistent with excitation of the repulsive A(2) summation operator(12) and (2) (2)Pi states of HCl(+), and the (3) (2)Pi state of HBr(+). Rotational alignment of the Omega=0(+) intermediate states is evident from the angular distribution of the excited H(*)(n=2) photofragments. This effect has been observed previously and was used here to verify the reliability of the measured spatial anisotropy parameters.

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Section: Introductionmentioning

confidence: 99%

Proton formation in 2+1 resonance enhanced multiphoton excitation of HCl and HBr via (Ω=) Rydberg and ion-pair states

Romanescu

Loock

2007

The Journal of Chemical Physics

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“…Since HBr plays an important role in the depletion mechanism, the information on this molecule would be helpful for monitoring the ozone layer depletion. Hence, it is not a surprise that a number of theoretical [68,83,84,[104][105][106][107] 17 (for an excellent illustration of the performance by the various approaches for HBr see [108]) and experimental [74,109,110] investigations have been carried out for the X 1 R þ HBr molecule in the past several years. Of these investigations, however, only a few experiments and theories are involved in evaluating the ground-state spectroscopic properties of X 1 R þ HBr.…”

Section: Ground-state Hydrogen Bromide[x 1 R þ Hbr]mentioning

confidence: 99%

State-specific complete active space multireference Møller–Plesset perturbation approach for multireference situations: illustrating the bond breaking in hydrogen halides

Chattopadhyay

Mahapatra²,

Chaudhuri

2012

Theor Chem Acc

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Assessment of the complete active space-based state-specific multireference Møller-Plesset perturbation theory, SS-MRMPPT, has been performed on the ground states of HX (X = F, Cl, and Br) systems through the computation of potential energy surface (PES) and spectroscopic constants (such as equilibrium bond lengths, rotational constants, centrifugal distortion constants, vibrational frequencies, anharmonicity constants, and dissociation energies that are closely related to the shape and accuracy of the energy surfaces) extracted from the computed PES. The SS-MRMPPT (involves multiple amplitude sets to parametrize the exact wavefunction) approach isolates one of the several states provided by an effective Hamiltonian in an attempt to avert intruder states in sizeextensive manner and hence it forms the basis of a robust approach to the electron correlation problem in cases where a multireference formalism is required. The absence of intruder problem makes SS-MRMPPT an interesting choice for the calculation of the dissociation energy surface(s). The performance of the method has been judged by comparing the results with calculations provided by current generation ab initio methods (multireference or singlereference methods) and we found, in general, a very good accordance between them which clearly demonstrates the usefulness of the SS-MRMPPT method.

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“…Consequently optical (rovibronic) excitation of ground state HBr þ ions into the A 2 AE þ state opens access to predissociation in the region of the threshold of fragmentation (Penno, Holzwarth, & Weitzel, 1998;Penno & Weitzel, 2004). From photoelectron spectroscopy it was known that the A 2 AE þ (v ¼ 2) state predissociates fast for all rotational eigenstates (Baltzer et al, 1994;Yencha et al, 1998). Thus one could expect to be able to locate the dissociation threshold within the rotational manifold of the A 2 AE þ (v ¼ 1) state.…”

Section: Bond-dissociation Energies Of Cationsmentioning

confidence: 99%

Bond‐dissociation energies of cations—Pushing the limits to quantum state resolution

Weitzel

2011

Mass Spectrometry Reviews

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Currently available concepts for measuring the bond-dissociation energy of cations D(o) are reviewed. Starting from the traditional approach of directly measuring the threshold energy for the appearance of fragment ions, attention is directed towards indirect measurements, where threshold energies are obtained by extrapolation of, for example, rate constants k(E) or kinetic energy release (KER) data to the threshold of interest. More recent high precision techniques again utilize direct measurements, for example, of the disappearance energy of the parent ion. Most precise data are obtained from quantum state resolved measurements of the dissociation energy, where the threshold energy is bracketed by the existing quantum states above and below the threshold. Ultimately the limits can even be pushed beyond the bracketing limit, by investigating steps on the lineshape of homogeneously broadened single rotational transitions.

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Threshold photoelectron spectroscopy of HBr and DBr

Cited by 36 publications

References 53 publications

Proton formation in 2+1 resonance enhanced multiphoton excitation of HCl and HBr via (Ω=) Rydberg and ion-pair states

Proton formation in 2+1 resonance enhanced multiphoton excitation of HCl and HBr via (Ω=) Rydberg and ion-pair states

State-specific complete active space multireference Møller–Plesset perturbation approach for multireference situations: illustrating the bond breaking in hydrogen halides

Bond‐dissociation energies of cations—Pushing the limits to quantum state resolution

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