Development history of the molecular beam laser photoionization time-of-flight mass spectrometer in Lab 108, IAMS

　

Instrument

Pulsed molecular beam multiphoton ionization (MPI) TOF mass spectrometer, 1990-1992

Statement

(1) High vacuum system, (2) Molecular beam system, (3) UV laser system, (4) Time-of-flight mass spectrometer, (5) Molecular beam, laser and ion timing control device, (6) Ion collection data system
Study the stable structure of molecular cluster ions, the intermolecular force in the cluster, the dissociation process, etc.
　

Instrument

Pulsed molecular beam one-color resonance-enhanced multiphoton ionization (REMPI) TOF mass spectrometer, 1993-1995

Statement

(1) Add a second UV laser system, (2) Write computer programs to control UV laser and TOF mass spectrometer, (3) Learn Gaussian quantum chemical calculation programs, (4) Start to plot normal vibrations based on the output files of calculations
Accurately measure the electronic transition energy and record vibronic spectrum

　

Instrument

Pulsed molecular beam two-color REMPI TOF mass spectrometer, 1996-1997

Statement

1) Record the vibronic spectrum, (2) Re-adjust delayed time among the pulsed molecular beam, two lasers and ions, (3) Design a simple pulse laser light intensity detector,  (4) Design a simple molecular beam detector, (5) Normalize the obtained vibronic spectrum by dividing laser intensity, (6) Design two sets of pulsed high voltage power supplies with low interference noise.
Accurately measure the adiabatic ionization energy to distinguish impurities and to identify molecular isomers.

　

Instrument

Pulsed molecular beam two-color resonance-enhanced multiphoton mass-analyzed threshold ionization (MATI) TOF spectrometer, 1998-1999

Statement

 (1) Re-design the TOF electronic optics lens assembly, (2 ) Re-adjust delayed time among the pulsed molecular beam, two lasers, two pulsed high-voltage power supply triggering device and ions
Measure the adiabatic ionization energy more accurately and record the vibrationally resolved ionic spectra of different molecular isomers.

　

Instrument

Pulsed molecular beam two-color resonance-enhanced multiphoton MATI TOF spectrometer with specially designed a sample holder, 2014-2015

Statement

(1) Design a special sample holder, (2) Learn to use glove boxes to fill sandwich-type organometallic compound, (3) Learn to use Gaussian quantum chemical calculation programs to predict the molecular properties of sandwich-type organometallic complex.
 Accurately measure the adiabatic ionization energy vibrationally resolved ion spectrum of sandwch-type organometallic complex

　


In the process of building a TOF mass spectrometer, June 05, 1991, in Laboratory 108 of IAMS, Academia Sinica

In the process of building a TOF mass spectrometer, 1991, in Laboratory 108 of IAMS, Academia Sinica
Control equipment rack and work desk, 1991, in Laboratory 108 of IAMS, Academia Sinica


　

　

Right_1: Professor A. W. Castleman, Jr. (my research mentor at Pennsylvania State University, USA)，Left_1: First research assistant, July 8, 1991, in Laboratory 108 of IAMS, Academia Sinica

　
First TOF mass spectrum, obtained on November 07, 1991, in Laboratory 108 of IAMS, Academia Sinica
Possible sources of interference: 1. power supply of pulsed molecular beam valve, 2. power supply of pulsed Nd:YAG laser

　

TOF mass spectrum of ammonia molecular cluster ions, 355 nm (Nd:YAG laser frequency tripled), acquired on November 28, 1991
 Note: 1. We solved the problems by giving up using the commercial power supply. Instead, we designed and built a low-interference power supply for the pulsed molecular beam valve.  2. We applied two different electrical pulses to trigger the Q-switch and flash lamp of the Nd:YAG laser. The delay time of the two pulsed were appropriately adjusted.

　

TOF mass spectrum of sorghum liquor, 355 nm (Nd:YAG laser frequency tripled), acquired on May 2, 1992
Note: Afterwards, we also made (1) pure ethanol and (2) 58% ethanol + 42% water. After analyzing the results, we found that the mass spectrum of sorghum wine marked with 58% alcohol showed mostly ethanol molecular cluster ions,
We let the newly built TOF mass spectrometer drink sorghum liquor to express our congratulations!

　

TOF mass spectrometer in 1993, in Laboratory 108 of IAMS, Academia Sinica

　

Work station of the TOF mass spectrometer in 1993, in Laboratory 108 of IAMS, Academia Sinica

　

First student in Laboratory 108 of IAMS, Academia Sinica

　

　

First REMPI spectrum obtained on December 07, 1995.
 “S1 ← S0 transition of phenylacetylene: Ab initio and resonant two-photon ionization studies”, K. Narayanan, G. C. Chang, K. C. Shieh, C. C. Tung, and W. B. Tzeng, Spectrochim. Acta A  52, 1703-1716 (1996).

　

First two-color resonance-enhanced multiphoton MATI spectrum, obtained on November 26-27, 1998.
 “Ionization energy of p-fluoroaniline and vibrational levels of p-fluoroaniline cation determined by mass-analyzed threshold ionization spectroscopy”, W. B. Tzeng and J. L. Lin, J. Phys. Chem. A 103, 8612-8619 (1999).


　

First photoionization efficiency (PIE) spectrum of sandwich-type organometallic complex bis(benzene)chromium, obtained on March 25, 2015.


　

First MATI spectrum of sandwich-type organometallic complex bis(benzene)chromium, obtained on March 25, 2015.


　

PIE spectrum of sandwich-type organometallic complex (benzene)(biphenyl)chromium, obtained on April 22, 2015.
 “Fine substituent effects in sandwich complexes: First threshold ionization study of monosubstituted chromium bisarene compounds”, Sergey Yu. Ketkov, Gennady V. Markin, Sheng Y. Tzeng, and Wen B. Tzeng, Chem. Eur. J. 22, 4690-4694 (2016).


　

MATI spectrum of sandwich-type organometallic complex (benzene)(biphenyl)chromium, obtained on April 22, 2015.
 “Fine substituent effects in sandwich complexes: First threshold ionization study of monosubstituted chromium bisarene compounds”, Sergey Yu. Ketkov, Gennady V. Markin, Sheng Y. Tzeng, and Wen B. Tzeng, Chem. Eur. J. 22, 4690-4694 (2016).

　

Mass and optical spectra of (mesitylene)(toluene)chromium sandwich compound sample, obtained on April 16, 2019.
Right: laser wavelength fixed at 240 nm, 264 amu: (mesitylene)(toluene)chromium;
292 amu : bis(mesitylene)chromium; 172 amu : (mesitylene)chromium; 92 amu : toluene; 52 amu : chromium

　

PIE spectra of (mesitylene)(toluene)chromium sandwich compound sample, obtained on April 17, 2019.
Upper half on Right: mass gated at 264 amu，PIE spectra of (mesitylene)(toluene)chromium
Lower half on Right: mass gated at 292 amu，PIE spectra of bis(mesitylene)chromium

　

MATI spectra of (mesitylene)(toluene)chromium sandwich compound sample, obtained on April 16, 2019.
Upper half on Right: mass gated at 264 amu，MATI spectra of (mesitylene)(toluene)chromium
Lower half on Right: mass gated at 292 amu，MATI spectra of bis(mesitylene)chromium

　

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