Weizhong Sun

• PhD
• Engineer at Finisar

Collision-induced rotational energy transfer of CO (A'Pi , v = 3) with He, Ne and Ar is studied experimentally via two-color 2 + 1 + 1 REMPI technique. The propensity of +/- parity-conservation is observed. The cross-sections sigma(Pi(+), Pi(+)) > sigma(Pi(-) --> Pi(-)), and the abnormal phenomenon of sigma(Deltaj=0)(+/--->-/+) < sigma(Deltaj=+/-1)...

The photodissociation dynamics of 1,3-butadiene at 193 nm have been investigated with photofragment translational spectroscopy coupled with product photoionization using tunable VUV synchrotron radiation. Five product channels are evident from this study: C(4)H(5) + H, C(3)H(3) + CH(3), C(2)H(3) + C(2)H(3), C(4)H(4) + H(2), and C(2)H(4) + C(2)H(2)....

Photofragment translational spectroscopy has been used to investigate the dissociation dynamics of 1,2-butadiene at 193 nm. Ionization of scattered photoproducts was accomplished using tunable VUV synchrotron radiation at the Advanced Light Source. Two product channels are observed: CH3+C3H3 and C4H5+H. The C3H3 product can be identified as the pro...

Reagent orbital alignment effects in chemiluminescence reactions Ca(1P1) + CH3X (X = Cl, I) are studied in a beam-gas apparatus. Stronger alignment dependence is found in the reaction Ca(1P1) + CH3Cl. For an ideal case, a simple expression is derived to calculate the reagent alignment sensitivity factor. This analysis shows that the primary reasons...

The photodissociation dynamics of propyne and allene are investigated in two molecular beam/photodissociation instruments, one using electron impact ionization and the other using tunable vacuum ultraviolet (VUV) light to photoionize the photoproducts. The primary dissociation channels for both reactants are C3H3+H and C3H2+H2. Measurement of the p...

Propargyl chloride, HCCCH2Cl, propargyl bromide, HCCCH2Br, and allene, H2CCCH2, are photolized by a 193 and 248 nm excimer laser to produce propargyl radical, H2CCCH, with a crossed laser-molecular beam apparatus. Photofragments are ionized in a quadrupole mass spectrometer by energy-controlled photons from an advanced light source. In the case of...

We have investigated the photodissociation of vinyl chloride (H2CCHCl) at 193 nm using the technique of photofragment translational spectroscopy. The experiments were performed at the Chemical Dynamics Beamline at the Advanced Light Source and used vacuum ultraviolet synchrotron radiation for product photoionization. We have observed five primary d...

Experimental results of the reaction Ca(1P1) + CH3I show that the reagent orbital alignment of Ca(1P1) can influence the product vibrational distributions. In the A2∏ state of CaI product, the vibrational distribution is shifted from low to high levels as the alignment of the p orbital of Ca(1P1) is changing from parallel to perpendicular, relative...

By using a two‐color scheme, we have given a closer scrutiny to the Autler–Townes doublet splitting and ac Stark shift in the 2+2‐photon ionization spectra of CO Ion A 1(v′=4)←X 1Σ+(v″=0) transition in the presence of another strong laser field, which is resonant with the transition C 1Σ+(v′=0)←A 1Π(v′=4)P10 branch. All the observations of ac Stark...

Collision-induced rotational energy transfer of CO (A1Π) is studied by two-color double resonance multiphotoionization spectroscopy. With He as a collision partner, the cross sections for CO (A1Π, v = 3) from J = 2, M = 2, e to J′ = 1, M′ = 1, e and J′ = 1, M′ = −1, e, are 162 + 0.32 and 0.89 + 0.18A˚2 respectively. The corresponding values for CO*...

An optical–optical double resonance multiphoton ionization (OODR-MPI) technique has been developed for measuring the angular momentum reorientation in CO(A 1&Pgr;)–He inelastic thermal collisions. In this scheme, two-photon pumping of CO(A 1&Pgr;) by using a circularly polarized laser creates a highly anisotropic oriented angular momentum distribut...

A study of 3+m-photon ionization spectra of CO (A←X) transitions in CO+Xe mixtures shows strong Xe enhancement and the appearance of extra ionization ‘‘lines’’ to the violet end of the respective CO (A←X) vibrational bands. Both facts are adequately interpreted as the result of reabsorption of laser-induced third harmonic generation (THG) in CO+Xe...

IR stimulation and quenching of different Nd3+ centers in ZnS have been studied. The mechanism of the IR effect has been discussed.