Effect of nuclear motion observed in high-order harmonic generation from D₂/H₂molecules with intense multi-cycle 1300 nm and 800 nm pulses

Abstract

We investigate high-order harmonic generation from D 2 /H 2 molecules with intense multi-cycle pulses centred both at 1300 nm (60 fs) and at 800 nm (50 fs) together with that from N 2 /Ar as a reference. The experimental observations with 1300 nm pulses are different from those with 800 nm pulses both in spectral shapes and in intensity ratios I D 2 /I H 2 . The effect of nuclear motion in D 2 and H 2 is more distinctive for 1300 nm pulses than for 800 nm pulses. With multi-cycle pulses of 50-60 fs, the intensity ratios I D 2 /I H 2 are found to be higher for both 800 nm and 1300 nm pulses than those with few-cycle pulses of 8 fs, which is attributed partly to the contribution of the coupling between the 1sσ g and 2pσ u states in D + 2 and H + 2 molecular ions during the higher order returns of the electron wave packets.

Monitoring ultrafast vibrational dynamics of isotopic molecules with frequency modulation of high-order harmonics

“…2d . One can see that the harmonic intensities from D 2 are higher than those from H 2 , which is in consistent with previous studies 27 – 29 , 36 , 37 . More importantly, the measured harmonics from H 2 and D 2 present obvious frequency shift with respect to those from Ar.…”

Effect of nuclear motion on high-order-harmonic generation ofH2+in intense ultrashort laser pulses

“…While, our results show that when nuclear motion is taken into account, higher HHG yield is obtained for heavier isotopomer which is compatible with experimental reports [8,[24][25]. The 1D electronic NBO calculations overestimate the recollision-recombination effect relative to full-dimensional electronic NBO calculations, especially at longer return times of the released electron corresponding to increased internuclear distance, which is detrimental to the recollision-recombination phenomenon, and thus attenuates the HHG production.…”

“…We solved numerically time-dependent Schrödinger equation for H [8,[24][25]. While, our results show that when nuclear motion is taken into account, higher HHG yield is obtained for heavier isotopomer which is compatible with experimental reports [8,[24][25].…”

Attosecond Nuclear Dynamics in the Ammonia Cation: Relation between High‐Harmonic and Photoelectron Spectroscopies

“…This principle enables the observation of nuclear dynamics in the molecular cation with a temporal resolution on the order of 100 as, as experimentally demonstrated in D 2 /H 2 and CD 4 /CH 4 [4]. The measurements on molecular hydrogen have been further investigated in terms of two-center interference [5] and extended to 1.3 µm [6]. The nuclear dynamics were also investigated in mixtures of D 2 and H 2 in order to access phase differences of the high harmonics emitted in both species [7].…”

“…[4] The measurements on molecular hydrogen have been further investigated in terms of two-center interference [5] and extended to 1.3 mm. [6] The nuclear dynamics were also investigated in mixtures of D 2 and H 2 in order to access phase differences of the high harmonics emitted in both species. [7] Using the reconstruction of attosecond beating by interference of two photon transitions (RABITT) technique, the relative spectral phases of D 2 and H 2 were investigated in ref.…”