Non-adiabatic effects on resonant two-photon dissociation of HD⁺in the presence of two frequency laser fields

Abstract

The time-dependent dissociation probabilities, lineshapes of dissociation rates and branching ratios of photofragments between the neutral hydrogen and deuterium channels have been investigated for resonant two-photon dissociation of HD+ from the ground level in the presence of two laser fields of different intensities I1, I2 and frequencies omega 1, omega 2 using the resolvent operator formalism. The symmetry breaking due to non-adiabatic (NA) interactions causes splitting between the two asymptotic channels, unlike the Born-Oppenheimer (BO) approximation. Simultaneous dissociation to the continua of the two electronic states at two different energies occurs through the absorption of either omega 1+ omega 2 or 2 omega 1 photons. Only the field of frequency omega 1 was considered to resonantly couple the near-resonant level nu '=17, J'=1 or nu '=18, J'=1 to the ground level nu =0, J=0. Non-resonant discrete and continuum states significantly affect the dissociation process in the case of high intensity fields. The electric field gauge (E.d) form of interaction Hamiltonian has been used in the computation of various laser-dependent parameters. The results with NA coupling included are found to deviate appreciably from those obtained with the BO approximation.

Above-Threshold Dissociation of HD + in Femtosecond Laser Field

“…In the calculations, the transition and permanent dipole moments are taken from Refs. [24,25]. There are 30 Legendre polynomials used to describe the angular part.…”

A time-independent Hermitian Floquet approach for high harmonic generation in H2+ and HD+: Effect of nonadiabatic interaction in HD+

“…46 The NA potentials of the ground ͑GS͒ and the excited ͑ES͒ states of HD + are obtained from Carrington and Kennedy 46 as well as from Moss and Sadler. 47 The electronic transition ͑1s g → 2p u ͒ dipole moments of H 2 + are given by Bates, 48 while the transition ͑GS → ES͒ and intrinsic dipole moments of the states GS and ES of HD + are obtained from Bates 48 by the method given in the Appendix A of the work of Ghosh et al 36 It may be noted here that, unlike neutral HD, 12 the HD + ion has a large permanent dipole moment of about 0.87 D ͑at v =0, J =0͒. 49,50 As used by many workers, 5,10,12,22,23,31,33 we have employed the length gauge of the interaction Hamiltonian to calculate the HHG spectra of H 2 + and HD + .…”

“…It mixes the two CR states and the heteronuclearity ͑unequal nuclear masses͒ of the molecular ion causes the symmetry breaking. 36 The HHG spectra of HD + have also been compared with those obtained using the BO approximation.…”

Above-threshold multiphoton dissociation of and in intense laser fields

“…The transition dipole moments of H + 2 are taken from Bates [22]. The intrinsic and transition dipole moments of HD + are obtained from the work of Bates [22] by the method given in [23].…”