Description of molecular dynamics in intense laser fields by the time-dependent adiabatic state approach: application to simultaneous two-bond dissociation of CO2 and its control.
ABSTRACT We theoretically investigated the dynamics of structural deformations of CO(2) and its cations in near-infrared intense laser fields (approximately 10(15) W cm(-2)) by using the time-dependent adiabatic state approach. To obtain "field-following" adiabatic potentials for nuclear dynamics, the electronic Hamiltonian including the interaction with the instantaneous laser electric field is diagonalized by the multiconfiguration self-consistent-field molecular orbital method. In the CO(2) and CO(2+) stages, ionization occurs before the field intensity becomes high enough to deform the molecule. In the CO(2)(2+) stage, simultaneous symmetric two-bond stretching occurs as well as one-bond stretching. Two-bond stretching is induced by an intense field in the lowest time-dependent adiabatic state |1> of CO(2)(2+), and this two-bond stretching is followed by the occurrence of a large-amplitude bending motion mainly in the second-lowest adiabatic state |2> nonadiabatically created at large internuclear distances by the field from |1>. It is concluded that the experimentally observed stretched and bent structure of CO(2)(3+) just before Coulomb explosions originates from the structural deformation of CO(2)(2+). We also show in this report that the concept of "optical-cycle-averaged potential" is useful for designing schemes to control molecular (reaction) dynamics, such as dissociation dynamics of CO(2), in intense fields. The present approach is simple but has wide applicability for analysis and prediction of electronic and nuclear dynamics of polyatomic molecules in intense laser fields.
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ABSTRACT: Tumor-infiltrating lymphocytes (TILs) have been found to increase survival in many forms of cancer, including, endometrial, bile ductal, colonic, esophageal, and urothelial cancers, as well as melanoma and follicular lymphoma. The relevance of TILs in the prognosis of non-small-cell lung cancer (NSCLC), however, still remains controversial. We compared the outcomes of stage 1A NSCLC with and without tumor infiltrating lymphocytes to evaluate the effects of TILs on recurrence and survival patterns. From 2000 to 2009, 273 anatomic segmentectomies and lobectomies were performed on stage 1A NSCLC. Patients were stratified into TIL- and TIL+ cohorts based on pathologic evaluation. Further investigation was conducted on the effects of TILs in patients with and without angiolymphatic invasion. Variables analyzed include overall survival, recurrence-free survival, and type of recurrence. Overall 5-y survival was not affected by TIL status (65% versus 60%, P = 0.469). Five-year recurrence-free survival (RFS) was significantly increased in the TIL+ group versus the TIL- group (87% versus 73%, P = 0.011), most significantly in women (P = 0.016). The presence of angiolymphatic invasion (ALI) was associated with decreased 5-y RFS versus patients without ALI (61% versus 85%, P < 0.001). Interestingly, in the ALI negative group, TIL+ patients experienced a significantly increased 5-y recurrence-free survival versus TIL- patients (93% versus 80%, P = 0.036). High levels of intratumoral TILs are associated with improved recurrence-free survival in stage 1A NSCLC patients as well as a reduced likelihood of systemic recurrence. When angiolymphatic invasion is not present, the beneficial effects of TILs become even more profound.Journal of Surgical Research 04/2011; 171(1):1-5. · 2.02 Impact Factor
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ABSTRACT: Impulsive Raman excitation of C(60) by single or double pulses of near-infrared wavelength λ = 1800 nm was investigated by using a time-dependent adiabatic state approach combined with the density functional theory method. We confirmed that the vibrational energy stored in a Raman active mode of C(60) is maximized when T(p) ~ T(vib)/2 in the case of a single pulse, where T(p) is the pulse length and T(vib) is the vibrational period of the mode. In the case of a double pulse, mode selective excitation can be achieved by adjusting the pulse interval τ. The energy of a Raman active mode is maximized if τ is chosen to equal an integer multiple of T(vib) and it is minimized if τ is equal to a half-integer multiple of T(vib). We also investigated the subsequent picosecond or nanosecond dynamics of Stone-Wales rearrangement (SWR) and fragmentation by using the density-functional based tight-binding semiempirical method. We present how SWRs are caused by the flow of vibrational kinetic energy on the carbon bond network of C(60). In the case where the h(g)(1) prolate-oblate mode is initially excited, the number of SWRs before fragmentation is larger than in the case of a(g)(1) mode excitation for the same excess vibrational energy. Fragmentation by C(2) ejection C(60) → C(58) + C(2) is found to occur from strained, fused pentagon/pentagon defects produced by a preceding SWR, which confirms the earliest mechanistic speculations of Smalley et al. [J. Chem. Phys. 88, 220 (1988)]. The fragmentation rate of C(2) ejection in the case of h(g)(1) mode excitation does not follow a statistical description as employed for instance in the Rice-Ramsperger-Kassel (RRK) theory, whereas the rate for a(g)(1) mode excitation does follow the prediction by RRK. We also found for the h(g)(1) mode excitation that the nonstatistical nature affects the distribution of barycentric velocities of fragments C(58) and C(2). This result suggests that it is possible to control rearrangement and subsequent bond breaking in a "nonstatistical" way by initial selective mode excitation.The Journal of chemical physics 04/2012; 136(16):164304. · 3.09 Impact Factor
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ABSTRACT: We have made a series of measurements, as a function of pulse duration, of ionization and fragmentation of the asymmetric molecule N2O in intense femtosecond laser radiation. The pulse length was varied from 7 fs to 500 fs with intensity ranging from 4 × 10(15) to 2.5 × 10(14) W∕cm(2). Time and position sensitive detection allows us to observe all fragments in coincidence. By representing the final dissociation geometry with Dalitz plots, we can identify the underlying breakup dynamics. We observe for the first time that there are two stepwise dissociation pathways for N2O(3+): (1) N2O(3+) → N(+) + NO(2+) → N(+) + N(+) + O(+) and (2) N2O(3+) → N2 (2+) + O(+) → N(+) + N(+) + O(+) as well as one for N2O(4+) → N(2+) + NO(2+) → N(2+) + N(+) + O(+). The N2 (2+) stepwise channel is suppressed for longer pulse length, a phenomenon which we attribute to the influence which the structure of the 3+ potential has on the dissociating wave packet propagation. Finally, by observing the total kinetic energy released for each channel as a function of pulse duration, we show the increasing importance of charge resonance enhanced ionization for channels higher than 3+.The Journal of chemical physics 05/2013; 138(20):204311. · 3.09 Impact Factor