10 54 AM Imaging the Vibrational Predissociation of

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10: 54 AM Imaging the Vibrational Predissociation of the Water Dimer (H 2 O)2

10: 54 AM Imaging the Vibrational Predissociation of the Water Dimer (H 2 O)2 & (D 2 O)2 Lee Chiat Ch’ng Department of Chemistry University of Southern California 59 th Annual Western Spectroscopy Association Conference

10: 54 AM • Background • Experimental Details • Challenges of detecting water fragments

10: 54 AM • Background • Experimental Details • Challenges of detecting water fragments • Fitting images • HCl-H 2 O example • (H 2 O)2 & (D 2 O)2 results • Conclusion

10: 54 AM • H-bond is ubiquitous in the world. • Smallest H-bond water

10: 54 AM • H-bond is ubiquitous in the world. • Smallest H-bond water complex- (H 2 O)2 • No dissociation energy (D 0) measurement • Energy pathways not well studied • No good detection method • Background water

10: 54 AM • Zero point motion of (H 2 O)2 Bastiaan J. Braams,

10: 54 AM • Zero point motion of (H 2 O)2 Bastiaan J. Braams, Emory University http: //www. mathcs. emory. edu/~braams/misc/dimers. html

10: 54 AM UV IR + CP

10: 54 AM UV IR + CP

10: 54 AM • Time-of-flight Mass Spectrometry mode: Fix UV Scan IR Fix IR

10: 54 AM • Time-of-flight Mass Spectrometry mode: Fix UV Scan IR Fix IR Scan UV IR action spectrum of dimer • Fragment Imaging Mode: Fix UV Fix IR REMPI spectrum of fragment Velocity of fragment w/ specific ν, J state Reconstruct

10: 54 AM UV IR + 2723 cm-1 + 1 cm-1 Calculated D 0

10: 54 AM UV IR + 2723 cm-1 + 1 cm-1 Calculated D 0 2724 - 1189= 1535 cm-1 1535 - 225= 1310 cm-1 Erot(HCl) (j=0, 1, 2…)= 0, 23, 63 … cm-1 ETrans= 1310, 1287, 1247, … cm-1 225 cm-1

10: 54 AM UV IR + 2723 cm-1 + 1 cm-1 Calculated D 0

10: 54 AM UV IR + 2723 cm-1 + 1 cm-1 Calculated D 0 2724 - 1189= 1535 cm-1 1535 - 225= 1310 cm-1 Erot(HCl) (j=0, 1, 2…)= 0, 23, 63 … cm-1 ETrans= 1310, 1287, 1247, … cm-1 Convolute with Gaussians 225 cm-1

10: 54 AM UV IR + 2723 cm-1 + 1 cm-1 Calculated D 0

10: 54 AM UV IR + 2723 cm-1 + 1 cm-1 Calculated D 0 2724 - 1189= 1535 cm-1 1535 - 225= 1310 cm-1 Erot(HCl) (j=0, 1, 2…)= 0, 23, 63 … cm-1 ETrans= 1310, 1287, 1247, … cm-1 Convolute with Gaussians 225 cm-1

UV IR + 2723 cm-1 + 1 cm-1 Fitting for D 0 2724 -

UV IR + 2723 cm-1 + 1 cm-1 Fitting for D 0 2724 - 1334= 1390 cm-1 1390 - 225= 1165 cm-1 Erot(HCl) (j=0, 1, 2…)= 0, 23, 63 … cm-1 ETrans= 1165, 1142, 1102 … cm-1 Convolute with Gaussians 225 cm-1

10: 54 AM D 0 = 1334 ± 10 cm-1 Monitoring H 2 O

10: 54 AM D 0 = 1334 ± 10 cm-1 Monitoring H 2 O Monitoring HCl B E Casterline, A K Mollner, L C Ch’ng, H Reisler, J Chem Phys A, 111 (2010) 9774 B E Rocher-Casterline, A K Mollner, L C Ch’ng, H Reisler, J Chem Phys A, 113 (2009) 10174

10: 54 AM Bound OH(D) stretch Dimer excited st. lifetime Calculated D 0 Fragment

10: 54 AM Bound OH(D) stretch Dimer excited st. lifetime Calculated D 0 Fragment st. Fragment rot. spectrum (H 2 O)2 (D 2 O)2 3601 cm-1 [1] 2633 cm-1 [2] 80 ps [1] 5 ns [2] 1103 cm-1 [3] 1244 cm-1 [4] Predissociative Less Predissociative Congested Very congested [1] Z S Huang, R E Miller, J Chem Phys, 91 (1989) 6613 [2] J B Paul, A Provencal, C Chapo, A Petterson, R J Saykally, J Chem Phys, 109 (1998) 10201 [3] A Shank, Y Wang, A Kaledin, B J Braams, J M Bowman, J Chem Phys 130 (2009) 144314. [4] G Czako, Y Wang, J Bowmen, J Chem Phys 135 (2011) 151102.

10: 54 AM Excess energy ~ 2500 cm-1 3601 cm-1 IR + Calculated D

10: 54 AM Excess energy ~ 2500 cm-1 3601 cm-1 IR + Calculated D 0 = 1103 cm-1 [1] (010) 1600 cm-1 (000) + (000) [1] A Shank, Y Wang, A Kaledin, B J Braams, J M Bowman, J Chem Phys 130 (2009) 144314. (000)

10: 54 AM 3602 + 5 cm-1 ν 2 =0, J ka, kc= 53,

10: 54 AM 3602 + 5 cm-1 ν 2 =0, J ka, kc= 53, 2 IR Gaussians UV + Simulation w/ cofragment (000) OR Simulation w/ cofragment (010)

10: 54 AM 3602 + 5 cm-1 IR ν =0, J ka, kc= 53,

10: 54 AM 3602 + 5 cm-1 IR ν =0, J ka, kc= 53, 2 Gaussians UV + OR 2 : 1 D 0 = 1105 ± 10 cm-1

10: 54 AM 3602 + 5 cm-1 IR ν 2 =1, J ka, kc=

10: 54 AM 3602 + 5 cm-1 IR ν 2 =1, J ka, kc= 32, 1 Gaussians UV + D 0 = 1105 ± 10 cm-1

10: 54 AM D 0 = 1105 cm-1

10: 54 AM D 0 = 1105 cm-1

10: 54 AM D 0 = 1080 cm-1

10: 54 AM D 0 = 1080 cm-1

10: 54 AM D 0 = 1130 cm-1

10: 54 AM D 0 = 1130 cm-1

10: 54 AM D 0 = 1105 cm-1

10: 54 AM D 0 = 1105 cm-1

10: 54 AM 3602 cm-1 IR + Calculated D 0 = 1103 cm-1 [2]

10: 54 AM 3602 cm-1 IR + Calculated D 0 = 1103 cm-1 [2] (010) 1600 cm-1 (000) D 0 = 1105 ± 10 cm-1 [1] + (000) • Detected both (000) and (010) H 2 O fragments. • Ratio of (000)+(010) vs. (000)+(000) is ~2: 1. • Theory calculated high bending excitation. [3] [1] B E Rocher-Casterline, L C Ch’ng, A K Mollner, H Reisler, J Chem Phys 134 (2011) 211101. [2] A Shank, Y Wang, A Kaledin, B J Braams, J M Bowman, J Chem Phys 130 (2009) 144314. [3] G Czakó, Y Wang, J Bowmen, J Chem Phys 135 (2011) 151102. (000)

10: 54 AM Excess energy ~ 1390 cm-1 + 2634 cm-1[1] IR Calculated D

10: 54 AM Excess energy ~ 1390 cm-1 + 2634 cm-1[1] IR Calculated D 0 = 1244 cm-1 [2] (010) 1180 cm-1 (000) + (000) • Theory calculated high bending excitation. [1] J B Paul, A Provencal, C Chapo, A Petterson, R J Saykally, J Chem Phys, 109 (1998) 10201 [2] G Czakó, Y Wang, J Bowmen, J Chem Phys 135 (2011) 151102. (000)

10: 54 AM 2644 + 7 cm-1 ν 2 =1, J ka, kc= 11,

10: 54 AM 2644 + 7 cm-1 ν 2 =1, J ka, kc= 11, 0 Gaussians UV IR + 2+1 REMPI C←X(010) D 0 = 1244 ± 10 cm-1

10: 54 AM C 1 B 1 (000) ← X 1 A 1 (000)

10: 54 AM C 1 B 1 (000) ← X 1 A 1 (000) UV

10: 54 AM IR UV + D 0 = 1244 cm-1

10: 54 AM IR UV + D 0 = 1244 cm-1

10: 54 AM + 2634 cm-1[2] IR Calculated D 0 = 1244 cm-1 [1]

10: 54 AM + 2634 cm-1[2] IR Calculated D 0 = 1244 cm-1 [1] (010) 1180 cm-1 (000) D 0 = 1244 ± 10 cm-1 + (000) • Detected (000) and (010) D 2 O fragments. • Observed high J population in (000) D 2 O fragments. • Theory calculated high bending excitation. • Experiment is not able to extract this information. [1] G Czakó, Y Wang, J Bowmen, J Chem Phys 135 (2011) 151102. [2] J B Paul, A Provencal, C Chapo, A Petterson, R J Saykally, J Chem Phys, 109 (1998) 10201 (000)

10: 54 AM (H 2 O)2 • Experimental D 0 = 1105 ± 10

10: 54 AM (H 2 O)2 • Experimental D 0 = 1105 ± 10 cm-1 • Calculated D 0 = 1103 cm-1 [1] • (000) + (010) : (000) + (000) ≈2 : 1 • Calculation shows high bending excitation. (D 2 O)2 • Experimental D 0 = 1244 ± 10 cm-1 • Calculated D 0 = 1244 cm-1 [2] • Observed large population in high J of (000) fragment. Results agree with Ewing Propensity Rule, V>R>T High level theory calculates accurate D 0, but energy flow pattern remains as a challenge. [1] A Shank, Y Wang, A Kaledin, B J Braams, J M Bowman, J Chem Phys 130 (2009) 144314. [2] G Czakó, Y Wang, J Bowmen, J Chem Phys 135 (2011) 151102.

10: 54 AM Prof. Hanna Reisler Funding: NSF Amit Samanta Emory University: Prof. Joel

10: 54 AM Prof. Hanna Reisler Funding: NSF Amit Samanta Emory University: Prof. Joel Bowman Gabor Czako Blithe Rocher Andrew Mollner

10: 55 AM

10: 55 AM