The full state-resolved distribution of scattered CO, (00 0) molecules from collisions with highly vibrationally excited Na-2(V-n-30 and 45) is reported and investigated how internal energy content impacts the dynamics for collisional quenching of high energy molecules. Stimulated emission pumping was used to excite the Na-2 (V-" = 30, J =11) and Na-2(v" = 45, J =11). Under single-collision conditions, rotational levels of the vibrationally relaxed Na-2(p" 1) and Na, (v" 2) are identified. Levels attributable to upward vibrational transfer could not be observed. The change in Na, rotational energy was determined. Quantifying the simultaneous population change for low J states is accomplished by transient line profile measurements for individual states. The line width is a measure of the translational energy spread of the scattered molecules and the area under the line profile is a measure of the J -specific population. The nascent translational temperature T-pres (for presence) and T-dep ( for depletion) are determined from the measured line widths Delta v(pres), and Delta v(dres), respectively. The presence line widths Delta v(pres), were obtained by fitting the double-Gaussian function to the transient line profile data at t = 1 mu.s. The lab-frame translational temperature T for the presence of scattered CO, molecules and the relative (center-of-mass frame) translational temperatures T (re1) for Na-2 (v") /CO2, collisions were determined based on Delta v(pres), measurements. Average translational energy gains for the presence of CO2(00 degrees 0 J) following collisions with vibrationally excited Na, are determined using < E-re1 >=3/2k (T-re1 - T-rell). The comparison shows that the Na, vibrational energy that goes into the translational energy of the CO, strongly depends on the initial energy: the translational energy of the J -specific collision pruducts increases by 56% or more for a 35% increase in donor vibrational energy. The appearance rate constants for individual CO2 rotational states are determined. The total appearance rate constant for Na, (r= 30) is k(spp) = (6. 6 1. 5) X 10 (10) cm3 " molecule (1) " s (1). This result is comparable to that for Na, (p" = 45) where the appearance rate constant is k(spp) = (5. 9 1. 3) X 10(10) cm(3) " molecule (1) . s (1). The results show that the Na-2 p" CO2 collision frequency is not particularly sensitive to the amount of Na-2(V") vibrational energy. The full energy transfer distributions P(AE) for product energy gain confirm that the 4E distributions broaden rapidly for relatively small increases in donor energy for Na(2)p (Delta E)/CO2 collisions. P(Delta E) curves for Na, (;1=30) are shifted to lower AE values compared to Na, (p"45) data. The Delta E values in P (Delta E) include the change in CO2 rotational energy and the change in translational energy of Na2(v") and CO2 plus the change in rotational energy ofNa(2) (v"). Numerical integration of P (Delta E) over the full range of AE yields <Delta E >(trans) =590 cm (1);Abstract The full state-resolved distribution of scattered CO, (00 0) molecules from collisions with highly vibrationally excited Na2(7-30 and 45) is reported and investigated how internal energy content impacts the dynamics for collisional quenching of high energy molecules. Stimulated emission pumping was used to excite the Na-2 (p" = 30, J =11) and Na-2(p" = 45, J =11). Under single-collision conditions, rotational levels of the vibrationally relaxed Na, (p" 1) and Na, (p" 2) are identified. Levels attributable to upward vibrational transfer could not be observed. The change in Na, rotational energy was determined. Quantifying the simultaneous population change for low J states is accomplished by transient line profile measurements for individual states. The line width is a measure of the translational energy spread of the scattered molecules and the area under the line profile is a measure of the J -specific population. The nascent translational temperature T (for presence) and Td ( for depletion) are determined from the measured line widths Avp, and Avd, respectively. The presence line widths Avp, were obtained by fitting the double-Gaussian function to the transient line profile data at t = 1 mu.s. The lab-frame translational temperature T for the presence of scattered CO, molecules and the relative (center-of-mass frame) translational temperatures T 1 for Na-2 (p") /CO, collisions were determined based on Avp, measurements. Average translational energy gains for the presence of CO2(00 0 J) following collisions with vibrationally excited Na, are determined using (E 1)=3/2k (T 1 T ll). The comparison shows that the Na, vibrational energy that goes into the translational energy of the CO, strongly depends on the initial energy: the translational energy of the J -specific collision pruducts increases by 56% or more for a 35% increase in donor vibrational energy. The appearance rate constants for individual CO2 rotational states are determined. The total appearance rate constant for Na, (r= 30) is k p = (6. 6 1. 5) X 10 10 cm(3) " molecule i " s L. This result is comparable to that for Na, (p" = 45) where the appearance rate constant is k p = (5. 9 1. 3) X 10 ' cm(3) " molecule i " s 1. The results show that the Na2 p" CO2 collision frequency is not particularly sensitive to the amount of Na, (p") vibrational energy. The full energy transfer distributions P(AE) for product energy gain confirm that the 4E distributions broaden rapidly for relatively small increases in donor energy for Na, (p")/CO2 collisions. P(AE) curves for Na, (;1=30) are shifted to lower AE values compared to Na, (p"45) data. The 4E values in P (4E) include the change in CO2, rotational energy and the change in translational energy of Na2(v") and CO2 plus the change in rotational energy of Na, (J7). Numerical integration of P (AE) over the full range of AE yields <Delta E >(trans), =590 cm (1); in comparison, <Delta E >(trans),, =880 cm(1) for Na-2(p"=45). in comparison, <Delta E >(trans) =880 cm i for Na-2(v"=45).
